Hardware | Estatísticas | Usuários | Limites | Runlevels | Senha de Root | Compilação de Kernel | Reparos de Grub
Executando kernel e a informação do sistema# uname -a # Mostra a versão do kernel (e a versão BSD) # lsb_release -a # Informação completa de quaisquer distribuição # cat /etc/SuSE-release # Mostra a versão SuSe # cat /etc/debian_version # Mostra a versão DebianUsa /etc/
DISTR-release com DISTR= lsb (Ubuntu), redhat,
gentoo, mandrake, sun (Solaris), e assim por diante. Veja também
/etc/issue. # uptime # Mostra quanto tempo o sistema está executando, ou seja, quanto tempo faz que o sistema não é desligado # hostname # Mostra na tela o nome da máquina # hostname -i # Exibe o endereço IP da máquina (apenas no Linux) # man hier # Descrição da hierarquia dos arquivos no sistema # last reboot # Exibe o histórico da reinicialização do sistema
# dmesg # Hardware detectado e mensagens de inicialização # lsdev # Informação sobre a instalação do hardware # dd if=/dev/mem bs=1k skip=768 count=256 2>/dev/null | strings -n 8 # Leitura da BIOS
# cat /proc/cpuinfo # Modelo da CPU # cat /proc/meminfo # Informação da memória # grep MemTotal /proc/meminfo # Exibe a memória física # watch -n1 'cat /proc/interrupts' # Relógio interrompe continuamente mutável # free -m # Mostra o ‘tamanho’ usado e livre da memória (-m para MB) # cat /proc/devices # Dispositivos configurados # lspci -tv # Mostra os dispositivos PCI # lsusb -tv # Mostra os dispositivos USB # lshal # Mostra a lista de todos os dispositivos com suas propriedades # dmidecode # Mostra DMI/SMBIOS: como a informação da BIOS
# sysctl hw.model # Mostra o modelo da CPU # sysctl hw # Mostra várias informações do hardware # sysctl vm # Memória usada # dmesg | grep "real mem" # Memória do hardware # sysctl -a | grep mem # Configurações e informações sobre a memória do kernel # sysctl dev # Mostra os dispositivos configurados # pciconf -l -cv # Exibe dispositivos PCI # usbdevs -v # Exibe dispositivos USB # atacontrol list # Exibe dispositivos ATA # camcontrol devlist -v # Exibe dispositivos SCSI
# top # Exibe e atualiza os processos da CPU # mpstat 1 # Exibe os processos das capacidades relacionadas # vmstat 2 # a capacidade da memória virtual # iostat 2 # Exibe a capacidade I/O (2s intervalo) # systat -vmstat 1 # Resumo da capacidade do sistema BSD (1s intervalo) # systat -tcp 1 # Conexões tcp no BSD (tenta também –ip) # systat -netstat 1 # Ativa as conexões de rede BSD # systat -ifstat 1 # BSD tráfego de redes ativas # systat -iostat 1 # BSD taxa de transferência do disco e da CPU # tail -n 500 /var/log/messages # As últimas 500 linhas mensagens do registro # tail /var/log/warn # Mensagens de alerta do sistema, veja em syslog.conf
# id # Exibe o id, usuário e grupo ativo # last # Exibe o ultimo usuário logado # who # Exibe o usuário logado # groupadd admin # Adiciona um grupo admin e um usuário colin (Linux/Solaris) # useradd -c "Colin Barschel" -g admin -m colin # usermod -a -G <group> <user> # Adiciona um usuário ao grupo (Debian) # groupmod -A <user> <group> # Adiciona um usuário ao grupo (SuSE) # userdel colin # Exclui o usuário Colin # adduser joe # FreeBSD, adiciona o usuário ao sistema (interativamente) # rmuser joe # FreeBSD, deleta o usuário joe (interativamente) # pw groupadd admin # Usa pw no FreeBSD # pw groupmod admin -m newmember # Adiciona um novo membro ao grupo # pw useradd colin -c "Colin Barschel" -g admin -m -s /bin/tcsh # pw userdel colin; pw groupdel adminSenhas criptografadas estão armazenadas no /etc/shadow nos Linux e Solaris, no FreeBSD estão localizadas no /etc/master.passwd. Se o master.passwd for modificado manualmente (deleta a senha), executa
# pwd_mkdb -p master.passwd para repor o banco de
dados.# echo "Desculpe não acessa agora" > /etc/nologin # (Linux) # echo "Desculpe não acessa agora" > /var/run/nologin # (FreeBSD)
ulimit -a. Por exemplo, para trocar os arquivos limites dos 1024 para
10240 faça:
# ulimit -n 10240 # Isso é apenas validará dentro do Shell
O comando ulimit pode ser usado no em um script para trocar os limites do
script apenas./etc/security/limits.conf. Por exemplo: # cat /etc/security/limits.conf * hard nproc 250 # Limites de processos por usuários asterisk hard nofile 409600 # Aplicações limites de arquivos abertos
/etc/sysctl.conf. # sysctl -a # Visualiza todo o limite do sistema # sysctl fs.file-max # Visualiza o limite máximo de arquivos abertos # sysctl fs.file-max=102400 # Troca o limite máximo # echo "1024 50000" > /proc/sys/net/ipv4/ip_local_port_range #Faixa de portas # cat /etc/sysctl.conf fs.file-max=102400 # Permanece a entrada no sysctl.conf # cat /proc/sys/fs/file-nr # Como muitos arquivos descritos em uso
limits em csh ou tcsh ou igual ao
Linux, use ulimit no bash shell. /etc/login.conf. Um valor ilimitado
ainda é limitado pelo sistema de valor máximo. /etc/sysctl.conf ou /boot/loader.conf. A sintaxe é igual
ao Linux mas as chaves são diferentes.
# sysctl -a # Visualiza todo o limite do sistema # sysctl kern.maxfiles=XXXX # Número máximo de descritores no arquivo kern.ipc.nmbclusters=32768 # Permanece a entrada no /etc/sysctl.conf kern.maxfiles=65536 # Típico valor do squid kern.maxfilesperproc=32768 kern.ipc.somaxconn=8192 # Fila TCP. Melhor para apache/sendmail # sysctl kern.openfiles # Quantos arquivos descritos são usados. # sysctl kern.ipc.numopensockets # Quantos sockets estão em uso # sysctl -w net.inet.ip.portrange.last=50000 # Padrão é 1024-5000 # netstat -m # Capacidade de memória da redeVeja o FreeBSD handbook Chapter 11http://www.freebsd.org/handbook/configtuning-kernel-limits.html para detalhes.
/etc/system incrementará
o máximo de descrições por proc:: set rlim_fd_max = 4096 # Limite físico nos arquivos de descrições para o único proc set rlim_fd_cur = 1024 # Limite lógico nas filas descritas para o único proc
init que então começa o
rc que inicia todos os scripts pertencente a um runlevel. O scripts são
armazenados em um /etc/init.d e são ligados a um /etc/rc.d/rcN.d com N o número do
runlevel.# grep default: /etc/inittab id:3:initdefault:O atual runlevel pode ser alterado com
init. Por exemplo para ir do 3 para
o 5: # init 5 # Entra o runlevel 5
chkconfig para configurar os programas que inicializará o boot
pelo runlevel.
# chkconfig --list # Lista todos os scripts do init # chkconfig --list sshd # Relata o estado do sshd # chkconfig sshd --level 35 on # Configura sshd para level 3 e 5 # chkconfig sshd off # Desabilita sshd todos os runlevelsDebian e distribuições baseadas no Debian como Ubuntu ou Knoppix usa o comando
update-rc.d para gerenciar o script do runlevel. Por padrão começa em
2,3,4 e 5 e shutdown no 0,1 e 6. # update-rc.d sshd defaults # Ativa sshd como runlevel padrão # update-rc.d sshd start 20 2 3 4 5 . stop 20 0 1 6 . # Com argumentos explícitos # update-rc.d -f sshd remove # Desabilita sshd para todos runlevels # shutdown -h now (or # poweroff) # Desliga o sistema ou suspende
/etc/ttys.
Todos os scripts estão localizado no /etc/rc.d/ e no
/usr/local/etc/rc.d/ a terceira parte das aplicações. A ativação do
serviço está configurado no /etc/rc.conf e /etc/rc.conf.local.
Por padrão está configurado no /etc/defaults/rc.conf. O script responde
pelo menos para
start|stop|status.# /etc/rc.d/sshd status sshd is running as pid 552. # shutdown now # Entra no modo single-user # exit # volta para o modo multi-usuário # shutdown -p now # Desliga e suspende o sistema # shutdown -r now # ReiniciatO processo do
init pode ser usado para checar um dos seguintes runlevels.
Por exemplo # init 6 para reiniciar. USR2)TERM)INT)TSTP)HUP)init=/bin/shO kernel montará a partição e o
init
inicializará o bourne Shell em vez do rc e o runlevel. Usa o comando
passwd para trocar a senha e reinicia.Esqueça o modo single-user, você
precisa da senha para isso.# mount -o remount,rw / # passwd # ou deleta a senha de root no (/etc/shadow) # sync; mount -o remount,ro / # sync depois de remontar para somente leitura # reboot
# mount -u /; mount -a # montará / rw
# passwd
# reboot
# mount -o rw /dev/ad4s3a /mnt
# chroot /mnt # chroot into /mnt
# passwd
# reboot
# lsmod # lista todos os módulos carregados # modprobe isdn # Carrega um módulo
# kldstat #Lista todos os módulos carregados # kldload crypto # Para carregar um módulo
# cd /usr/src/linux # make mrproper # Limpa o antigo .config se existir # make oldconfig # Re-usa o antigo .config se existente # make menuconfig # ou xconfig (Qt) ou gconfig (GTK) # make # Cria uma imagem comprimida # make modules # Compila os módulos # make modules_install # Instala os módulos # make install # Instala o kernel # reboot
/usr/src) com csup
(como FreeBSD 6.2 ou posterior): # csup <supfile>Eu sigo o supfile:
*default host=cvsup5.FreeBSD.org # www.freebsd.org/handbook/cvsup.html#CVSUP-MIRRORS *default prefix=/usr *default base=/var/db *default release=cvs delete tag=RELENG_7 src-allModifica e refaz o kernel, copia a configuração de arquivo genérica para o novo nome e edita como se precisa (você pode também editar o arquivo
GENERIC
diretamente). Para reiniciar a construção e após a interrupção, adiciona a opção
NO_CLEAN=YES, o comando make evita a limpeza dos objetos já formados.
# cd /usr/src/sys/i386/conf/ # cp GENERIC MYKERNEL # cd /usr/src # make buildkernel KERNCONF=MYKERNEL # make installkernel KERNCONF=MYKERNELPara a reconstrução total SO:
# make buildworld # Constrói total o SO mas não o kernel # make buildkernel # Usa KERNCONF para ambos # make installkernel # reboot # mergemaster -p # Compare somente os arquivos essenciais e conhecidos # make installworld # mergemaster -i -U # Atualiza todas as configurações e outros arquivos # rebootPara pequenas alterações no fonte, você pode usar NO_CLEAN=yes para evitar a reconstrução de toda a árvore.
# make buildworld NO_CLEAN=yes # Não deleta os objetos antigos
# make buildkernel KERNCONF=MYKERNEL NO_CLEAN=yes
/dev e use o fdisk para localizar a
partição do linux] monte a partição linux, adicione o /proc e o /dev e use o
grub-install /dev/xyz. Suponha que o linux esta em
/dev/sda6:
# mount /dev/sda6 /mnt # Monta a partição linux em /mnt # mount --bind /proc /mnt/proc # monta o subsistema proc no /mnt # mount --bind /dev /mnt/dev # monta os dispositivos no /mnt # chroot /mnt # troca a partição root Linux # grub-install /dev/sda # reinstala grub com suas antigas configurações
Listando | Prioridade | Background/Foreground | Top | Kill
ps.
# ps -auxefw # Lista extensa de todos os processos em execução
No entanto o uso mais típico é com o pipe ou o pgrep: # ps axww | grep cron 586 ?? Is 0:01.48 /usr/sbin/cron -s # ps axjf # Todos processos no formato de árvore(Linux) # ps aux | grep 'ss[h]' # Localiza todos pids ssh sem o grep pid # pgrep -l sshd # Localiza os PIDs dos processos por (parte de) nome # echo $$ # O PID de sua shell # fuser -va 22/tcp # Lista os processos usando a porta 22 (Linux) # pmap PID # Mapa dos processos em memória (Caça vazamentos de memória) (Linux) # fuser -va /home # Lista os processos acessing a partição /home # strace df # Traça os sinais e chamadas de sistema # truss df # Mesmo que acima em FreeBSD/Solaris/Unixware
renice. Número negativos tem uma prioridade maior , o menor é
-20 e o "nice" tem um valor positivo.
# renice -5 586 # Maior Prioridade
586: Prioridade antiga 0, nova prioridade -5
Inicia o processo com uma prioridade definida com o nice. Positivo é "nice"
ou fraco, negativo fixa uma prioridade forte. Certifique se /usr/bin/nice
ou o shell embutido usou (Verifique com # which nice).
# nice -n -5 top # Prioridade forte(/usr/bin/nice) # nice -n 5 top # Prioridade fraca (/usr/bin/nice) # nice +5 top # tcsh tem nice embutido (mesmo que acima!)Enquanto o nice altera o agendamento da CPU, um outro comando útil é o ionice, irá fixar o IO do disco. Isto é muito útil para aplicações intensivas (ex. compilação). Voce pode selecionar uma classe (ociosa - melhor esforço - tempo real ), a página do manual é curta e bem explicativa.
# ionice c3 -p123 # ajusta a classe ociosa para o PID 123 (Linux Somente) # ionice -c2 -n0 firefox # Executa o firefox com melhor esforço e maior prioridade # ionice -c3 -p$$ # Ajusta o shell atual para prioridade ociosaO ultimo comando é muito útil para compilar (ou debugar) um longo projeto. Cada comando iniciado neste shell terá a prioridade herdada. $$ é o seu shell pid (tente echo $$).
# idprio 31 make # Compila com menor prioridade # idprio 31 -1234 # Ajusta o PID 1234 com menor prioridade # idprio -t -1234 # -t remove qualquer prioridade de tempo real/ociosa
bg e fg. Lista os processos com jobs.
# ping cb.vu > ping.log ^Z # ping é interrompido (parado) com [Ctrl]-[Z] # bg # Coloca em segundo plano e continua executando # jobs -l # Lista os processos em segundo plano [1] - 36232 Running ping cb.vu > ping.log [2] + 36233 Suspended (tty output) top # fg %2 # Traz o processo 2 de volta ao primeiro planoUse
nohup para iniciar o processo que tem que continuar a executar quando a
shell é fechada. # nohup ping -i 60 > ping.log &
top exibe informações dos processos em
execução. Veja também o programa htop de htop.sourceforge.net (a versão
mais poderosa do top) que roda em Linux e FreeBSD (ports/sysutils/htop/).
Enquanto o top é executado pressione a tecla "h" para uma visão geral da ajuda. Teclas
úteis são: kill ou
killall.
# ping -i 60 cb.vu > ping.log & [1] 4712 # kill -s TERM 4712 # mesmo que finalizar com -15 4712 # killall -1 httpd # Kill HUP processos por nome # pkill -9 http # Kill TERM processos por (parte de) nome # pkill -TERM -u www # Kill TERM processos usado por www # fuser -k -TERM -m /home # Kill cada processo acessando /home (para desmontar)Sinais importantes são:
HUP (desliga)INT (suspende)QUIT (fecha)KILL (força)TERM (software envia o sinal de término)Info de disco | Boot | Uso de disco | Arquivos abertos | Monta/remonta | Monta SMB | Monta imagem | Queima ISO | Criar image | Memória de Disco | Desempenho de Disco
chmod e chown. A umask padrão pode ser alterada para todos
os usuários em /etc/profile para Linux ou /etc/login.conf para FreeBSD. A umask padrão
geralmente é 022. A umask é subtraído de 777, assim a umask 022 resulta na permissão de
755. 1 --x executa # Modo 764 = executa/lê/escreve | lê/escreve | lê 2 -w- escreve # Para: |-- Dono --| |- Grupo-| |Outros| 4 r-- lê ugo=a u=usuário, g=grupo, o=outros, a=todos
# chmod [OPÇÃO] MODO[,MODO] ARQUIVO # MODO é na forma [ugoa]*([-+=]([rwxXst])) # chmod 640 /var/log/maillog # Restringir o log -rw-r----- # chmod u=rw,g=r,o= /var/log/maillog # O mesmo acima # chmod -R o-r /home/* # Remove recursivamente leitura para outros para todos os usuários # chmod u+s /path/to/prog # Fixa SUID bit no executável (saiba o que esta fazendo!) # find / -perm -u+s -print # Localiza todos os programas com o SUID bit # chown user:group /path/to/file # Altera a propriedade do usuário e o grupo no arquivo # chgrp group /path/to/file # Altera a propriedade da grupo no arquivo # chmod 640 `find ./ -type f -print` # Altera a propriedade para 640 em todos os arquivos # chmod 751 `find ./ -type d -print` # Altera a permissão para 751 para todos os diretórios
# diskinfo -v /dev/ad2 # Informação sobre o disco (Setor/tamanho) FreeBSD # hdparm -I /dev/sda # Informação sobre o disco IDE/ATA (Linux) # fdisk /dev/ad2 # Exibe e manipula a tabela de partições # smartctl -a /dev/ad2 # O SMART exibe as informação do disco
# unload # load kernel.old # boot
# mount | column -t # Exibe o sistema de arquivos montados no seu sistema # df # Exibe o espaço livre no disco e dispositivos montados # cat /proc/partitions # Exibe todas partições registradas (Linux)
# du -sh * # Lista o tamanho dos diretórios # du -csh # Tamanho total do diretório corrente # du -ks * | sort -n -r # Ordena tudo por tamanho em kilobytes # ls -lSr # Exibe arquivos, maiores por último
# umount /home/
umount: unmount of /home # Impossível desmontar porque um arquivo esta bloqueando o home
Falhou: Dispositivo Ocupado
# fstat -f /home # Para montar o ponto # fstat -p PID # Para uma aplicação com PID # fstat -u user # Para um nome de usuárioLocaliza arquivos de log aberto (ou outros arquivos abertos), pela palavra Xorg:
# ps ax | grep Xorg | awk '{print $1}'
1252
# fstat -p 1252
USER CMD PID FD MOUNT INUM MODE SZ|DV R/W
root Xorg 1252 root / 2 drwxr-xr-x 512 r
root Xorg 1252 text /usr 216016 -rws--x--x 1679848 r
root Xorg 1252 0 /var 212042 -rw-r--r-- 56987 w
O arquivo com inum 212042 é o único arquivo em /var: # find -x /var -inum 212042 /var/log/Xorg.0.log
fuser ou
lsof:
# fuser -m /home # Lista os processos acessando o /home
# lsof /home
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
tcsh 29029 eedcoba cwd DIR 0,18 12288 1048587 /home/eedcoba (guam:/home)
lsof 29140 eedcoba cwd DIR 0,18 12288 1048587 /home/eedcoba (guam:/home)
Sobre uma aplicação:
ps ax | grep Xorg | awk '{print $1}'
3324
# lsof -p 3324
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
Xorg 3324 root 0w REG 8,6 56296 12492 /var/log/Xorg.0.log
Sobre um arquivo único: # lsof /var/log/Xorg.0.log COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME Xorg 3324 root 0w REG 8,6 56296 12492 /var/log/Xorg.0.log
# mount /cdromOu localize o dispositivo em /dev ou com o dmesg
# mount -v -t cd9660 /dev/cd0c /mnt # cdrom # mount_cd9660 /dev/wcd0c /cdrom # outro método # mount -v -t msdos /dev/fd0c /mnt # disqueteEntrada no /etc/fstab:
# Device Mountpoint FStype Options Dump Pass# /dev/acd0 /cdrom cd9660 ro,noauto 0 0Para permitir o usuário fazer:
# sysctl vfs.usermount=1 # Ou inserir a linha "vfs.usermount=1" em /etc/sysctl.conf
# mount -t auto /dev/cdrom /mnt/cdrom # Típico comando para montar cdrom # mount /dev/hdc -t iso9660 -r /cdrom # Típico IDE # mount /dev/scd0 -t iso9660 -r /cdrom # Típico SCSI cdrom # mount /dev/sdc0 -t ntfs-3g /windows # Típico SCSIEntrada no /etc/fstab:
/dev/cdrom /media/cdrom subfs noauto,fs=cdfss,ro,procuid,nosuid,nodev,exec 0 0
# fdisk /dev/sda # Localiza a partição FreeBSD /dev/sda3 * 5357 7905 20474842+ a5 FreeBSD # mount -t ufs -o ufstype=ufs2,ro /dev/sda3 /mnt /dev/sda10 = /tmp; /dev/sda11 /usr # Outros slices
# mount -o remount,ro / # Linux # mount -o ro / # FreeBSDCopie os dados brutos a partir do cdrom em uma imagem iso:
# dd if=/dev/cd0c of=file.iso
# dd if=/dev/zero of=/swap2gb bs=1024k count=2000 # mkswap /swap2gb # Criar a área de Swap # swapon /swap2gb # Ative a swap. Agora em uso! # swapoff /swap2gb # Quando terminar, desative a swap # rm /swap2gb
# smbclient -U user -I 192.168.16.229 -L //smbshare/ # Lista os compartilhamentos
# mount -t smbfs -o username=winuser //smbserver/myshare /mnt/smbshare
# mount -t cifs -o username=winuser,password=winpwd //192.168.16.229/myshare /mnt/share
Adicionando com o pacote mount.cifs é possível armazenar as credenciais em um arquivo,
por exemplo/home/user/.smb: username=winuser password=winpwdE montar os seguintes:
# mount -t cifs -o credentials=/home/user/.smb //192.168.16.229/myshare /mnt/smbshare
# smbutil view -I 192.168.16.229 //winuser@smbserver # List os compartilhamentos
# mount_smbfs -I 192.168.16.229 //winuser@smbserver/myshare /mnt/smbshare
# mount -t iso9660 -o loop file.iso /mnt # Monta uma imagem de CD # mount -t ext3 -o loop file.img /mnt # Monta uma imagem com sistema de arquivos ext3
# mdconfig -a -t vnode -f file.iso -u 0
# mount -t cd9660 /dev/md0 /mnt
# umount /mnt; mdconfig -d -u 0 # Limpeza do dispositivo md
Ou com nó virtual: # vnconfig /dev/vn0c file.iso; mount -t cd9660 /dev/vn0c /mnt
# umount /mnt; vnconfig -u /dev/vn0c # Limpeza do dispositivo vn
# lofiadm -a file.iso
# mount -F hsfs -o ro /dev/lofi/1 /mnt
# umount /mnt; lofiadm -d /dev/lofi/1 # Limpeza do dispositivo lofi
conv=notrunc, a imagem será menor se ouver conteúdo no
cd. Veja abaixo o dd examples.
# dd if=/dev/hdc of=/tmp/mycd.iso bs=2048 conv=notruncUse mkisofs para criar uma imagem CD/DVD de arquivos em um diretório. Para evitar a restrições de nomes de arquivos: -r permite a extensão Rock Ridge comuns ao sistema UNIX, -J permite extensão Joliet usada por sistemas Microsoft. -L permite arquivos ISO9660 começando com um período.
# mkisofs -J -L -r -V TITLE -o imagefile.iso /path/to/dirEm FreeBSD, mkisofs é encontrado no ports em sysutils/cdrtools.
hw.ata.ata_dma="1" hw.ata.atapi_dma="1"Use
burncd com um dispositivo ATAPI(burncd é parte da base do
sistema) e cdrecord ( em sysutils/cdrtools) com um disco SCSI. # burncd -f /dev/acd0 data imagefile.iso fixate # Para discos ATAPI # cdrecord -scanbus # Para localizar o dispositivo (like 1,0,0) # cdrecord dev=1,0,0 imagefile.iso
cdrecord com Linux como descrito acima. Além
disso é possível usar a interface ATAPI nativa que se encontra com:
# cdrecord dev=ATAPI -scanbusE queime o CD/DVD como acima.
growisofs para queimar CDs ou DVDs. Os exemplos se referem aos
dispositivos de DVD /dev/dvd que poderia ser um link simbólico para
/dev/scd0 (típico scsi em Linux) ou /dev/cd0 (típico
FreeBSD) ou /dev/rcd0c (típico NetBSD/OpenBSD de caráter SCSI) ou
/dev/rdsk/c0t1d0s2 (Exemplo de um dispositivo Solaris SCSI/ATAPI CD-ROM
). Existe uma boa documentação com exemplos em FreeBSD handbook chapter
18.7http://www.freebsd.org/handbook/creating-dvds.html. # -dvd-compat finaliza o disco # growisofs -dvd-compat -Z /dev/dvd=imagefile.iso # Queima uma imagem iso existente # growisofs -dvd-compat -Z /dev/dvd -J -R /p/to/data # Queima diretamente
# dd bs=1k if=imagefile.nrg of=imagefile.iso skip=300
bchunk programhttp://freshmeat.net/projects/bchunk/ pode fazer isso. E no ports
do FreeBSD em sysutils/bchunk. # bchunk imagefile.bin imagefile.cue imagefile.iso
# dd if=/dev/random of=/usr/vdisk.img bs=1K count=1M # mdconfig -a -t vnode -f /usr/vdisk.img -u 0 # Cria o dispositivo /dev/md1 # bsdlabel -w /dev/md0 # newfs /dev/md0c # mount /dev/md0c /mnt # umount /mnt; mdconfig -d -u 0; rm /usr/vdisk.img # Cleanup the md deviceO arquivo de imagem base pode ser automaticamente montado durante o boot com uma entrada em /etc/rc.conf and /etc/fstab. Teste sua instalação com
# /etc/rc.d/mdconfig
start (primeiro delete o dispositivo md0 com # mdconfig -d -u
0).md_load="YES"/etc/rc.conf:
# mdconfig_md0="-t vnode -f /usr/vdisk.img" # /usr is not on the root partition
/etc/fstab: (Os 0 0 no final são importantes, diz ao fsck para ignorar este dispositivo,
como ainda não existe)
/dev/md0 /usr/vdisk ufs rw 0 0Também é possível aumentar o tamanho da imagem depois, dizer, por exemplo, 300 MB de maior dimensão.
# umount /mnt; mdconfig -d -u 0
# dd if=/dev/zero bs=1m count=300 >> /usr/vdisk.img
# mdconfig -a -t vnode -f /usr/vdisk.img -u 0
# growfs /dev/md0
# mount /dev/md0c /mnt # A maior partição de arquivos agora é 300MB
# dd if=/dev/zero of=/usr/vdisk.img bs=1024k count=1024
# mkfs.ext3 /usr/vdisk.img
# mount -o loop /usr/vdisk.img /mnt
# umount /mnt; rm /usr/vdisk.img # Limpeza
/dev/zero é muito mais rápido urandom, mas menos segura para
criptografia # dd if=/dev/urandom of=/usr/vdisk.img bs=1024k count=1024 # losetup /dev/loop0 /usr/vdisk.img # Cria e associa /dev/loop0 # mkfs.ext3 /dev/loop0 # mount /dev/loop0 /mnt # losetup -a # Verifica os loops utilizados # umount /mnt # losetup -d /dev/loop0 # Separa # rm /usr/vdisk.img
# mount_mfs -o rw -s 64M md /memdisk # umount /memdisk; mdconfig -d -u 0 # Limpeza do dispositivo md md /memdisk mfs rw,-s64M 0 0 # entrada /etc/fstab
# mount -t tmpfs -osize=64m tmpfs /memdisk
# time dd if=/dev/ad4s3c of=/dev/null bs=1024k count=1000
# time dd if=/dev/zero bs=1024k count=1000 of=/home/1Gb.file
# hdparm -tT /dev/hda # Somente Linux
Roteamento | Adicionar IP | Alterar MAC | Portas | Firewall | IP Forward | NAT | DNS | DHCP | Tráfego | QoS | NIS | Netcat
# ethtool eth0 # Mostra o estado da ethernet (substitui mii-diag) # ethtool -s eth0 speed 100 duplex full # Força 100Mbit Full duplex # ethtool -s eth0 autoneg off # Desabilita auto negociação # ethtool -p eth1 # Pisca o led da ethernet - muito útil quando suportado # ip link show # Mostra todas as interfaces no Linux (semelhante ao ifconfig) # ip link set eth0 up # Levanta o dispositivo (ou desce). O mesmo que "ifconfig eth0 up" # ip addr show # Mostra todos os endereços IP no linux (semelhante ao ifconfig) # ip neigh show # Semelhante ao arp -a
# ifconfig fxp0 # Verifica o campo "media" no FreeBSD # arp -a # Verifica o Roteador (ou host) entrada ARP (todos OS) # ping cb.vu # A primeira coisa a tentar... # traceroute cb.vu # Imprime o caminho de rota para o destino # ifconfig fxp0 media 100baseTX mediaopt full-duplex # 100Mbit full duplex (FreeBSD) # netstat -s # Estatísticas do Sistema para protocolo de redeComandos adicionais que nem sempre são instalados por padrão, mas fácil de encontrar:
# arping 192.168.16.254 # Ping na camada ethernet # tcptraceroute -f 5 cb.vu # Utiliza o TCP ao invés de icmp para rastrear firewalls
# route -n # Linux ou use "ip route" # netstat -rn # Linux, BSD and UNIX # route print # Windows
# route add 212.117.0.0/16 192.168.1.1 # route delete 212.117.0.0/16 # route add default 192.168.1.1Adiciona rota permanente em /etc/rc.conf
static_routes="myroute" route_myroute="-net 212.117.0.0/16 192.168.1.1"
# route add -net 192.168.20.0 netmask 255.255.255.0 gw 192.168.16.254 # ip route add 192.168.20.0/24 via 192.168.16.254 # mesmo que acima com ip route # route add -net 192.168.20.0 netmask 255.255.255.0 dev eth0 # route add default gw 192.168.51.254 # ip route add default via 192.168.51.254 dev eth0 # mesmo que acima com ip route # route delete -net 192.168.20.0 netmask 255.255.255.0
# route add -net 192.168.20.0 -netmask 255.255.255.0 192.168.16.254
# route add default 192.168.51.254 1 # 1 = saltos para o próximo gateway
# route change default 192.168.50.254 1
Entradas permanentes são estabelecidas em /etc/defaultrouter.
# Route add 192.168.50.0 mask 255.255.255.0 192.168.51.253 # Route add 0.0.0.0 mask 0.0.0.0 192.168.51.254Use add -p para criar uma rota persistente.
# ifconfig eth0 192.168.50.254 netmask 255.255.255.0 # Primeiro IP # ifconfig eth0:0 192.168.51.254 netmask 255.255.255.0 # Segundo IP # ip addr add 192.168.50.254/24 dev eth0 # Equivalente ao comando ip # ip addr add 192.168.51.254/24 dev eth0 label eth0:1
# ifconfig fxp0 inet 192.168.50.254/24 # Primeiro IP # ifconfig fxp0 alias 192.168.51.254 netmask 255.255.255.0 # Segundo IP # ifconfig fxp0 -alias 192.168.51.254 # Remove o segundo apelido IPPermanent entries in /etc/rc.conf
ifconfig_fxp0="inet 192.168.50.254 netmask 255.255.255.0" ifconfig_fxp0_alias0="192.168.51.254 netmask 255.255.255.0"
ifconfig -a
# ifconfig hme0 plumb # Enable the network card # ifconfig hme0 192.168.50.254 netmask 255.255.255.0 up # First IP # ifconfig hme0:1 192.168.51.254 netmask 255.255.255.0 up # Second IP
# ifconfig eth0 down # ifconfig eth0 hw ether 00:01:02:03:04:05 # Linux # ifconfig fxp0 link 00:01:02:03:04:05 # FreeBSD # ifconfig hme0 ether 00:01:02:03:04:05 # Solaris # sudo ifconfig en0 ether 00:01:02:03:04:05 # Mac OS X Tiger # sudo ifconfig en0 lladdr 00:01:02:03:04:05 # Mac OS X LeopardMuitas ferramentas existentes para Windows. Por Exemplo etherchangehttp://ntsecurity.nu/toolbox/etherchange. Ou procure por "Mac Makeup", "smac".
# netstat -an | grep LISTEN # lsof -i # Linux Lista todas as conexões de Internet # socklist # Linux Mostra lista de sockets abertos # sockstat -4 # FreeBSD Lista Aplicações # netstat -anp --udp --tcp | grep LISTEN # Linux # netstat -tup # Lista conexões ativas de/para sistemas (Linux) # netstat -tupl # Lista portas em escuta do sistema (Linux) # netstat -ano # Windows
# iptables -L -n -v # Status Open the iptables firewall # iptables -P INPUT ACCEPT # Abre tudo # iptables -P FORWARD ACCEPT # iptables -P OUTPUT ACCEPT # iptables -Z # Zera os contadores de pacotes para todas as regras # iptables -F # Limpa todas as Regras # iptables -X # Deleta todas as Regras
# ipfw show # Status # ipfw list 65535 # if answer is "65535 deny ip from any to any" the fw is disabled # sysctl net.inet.ip.fw.enable=0 # Disable # sysctl net.inet.ip.fw.enable=1 # Enable
# cat /proc/sys/net/ipv4/ip_forward # Verifica o IP encaminhado 0=off, 1=on
# echo 1 > /proc/sys/net/ipv4/ip_forward
ou edita /etc/sysctl.conf com: net.ipv4.ip_forward = 1
# sysctl net.inet.ip.forwarding # Verifica o IP encaminhado 0=off, 1=on # sysctl net.inet.ip.forwarding=1 # sysctl net.inet.ip.fastforwarding=1 # Para dedicação do roteador ou firewall Permanencia com entrada em /etc/rc.conf: gateway_enable="YES" # Defina como YES se essa máquina for um gateway.
# ndd -set /dev/ip ip_forwarding 1 # Defina o IP para o encaminhamento 0=off, 1=on
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # Para ativar o NAT # iptables -t nat -A PREROUTING -p tcp -d 78.31.70.238 --dport 20022 -j DNAT \ --to 192.168.16.44:22 # Port forward 20022 to internal IP port ssh # iptables -t nat -A PREROUTING -p tcp -d 78.31.70.238 --dport 993:995 -j DNAT \ --to 192.168.16.254:993-995 # Port forward of range 993-995 # ip route flush cache # iptables -L -t nat # Check NAT statusDeleta a porta para o encaminhamento com -D em vez de -A.
# natd -s -m -u -dynamic -f /etc/natd.conf -n fxp0 Ou edita /etc/rc.conf com: firewall_enable="YES" # Defina YES para ativar a função do firewall firewall_type="open" # Tipo de firewall (veja /etc/rc.firewall) natd_enable="YES" # Habilite natd (if firewall_enable == YES). natd_interface="tun0" # Interface pública ou endereço de IP para uso. natd_flags="-s -m -u -dynamic -f /etc/natd.conf"Porta em encaminhada com:
# cat /etc/natd.conf
same_ports yes
use_sockets yes
unregistered_only
# redirect_port tcp insideIP:2300-2399 3300-3399 # Faixa de porta
redirect_port udp 192.168.51.103:7777 7777
nameserver 78.31.70.238 search sleepyowl.net intern.lab domain sleepyowl.netVerifica o nome do domínio no sistema com:
# hostname -d # Igual ao dnsdomainname
# ipconfig /? # Exibe ajuda # ipconfig /all # Veja toda a informação incluindo o DNS
# /etc/init.d/nscd restart # Reinicia nscd, se utilizar - Linux/BSD/Solaris # lookupd -flushcache # OS X Tiger # dscacheutil -flushcache # OS X Leopard and newer # ipconfig /flushdns # Windows
213.133.105.2 ns.second-ns.de pode ser usado
para teste. Veja como o servidor cliente responde isso (uma simples resposta).
# dig sleepyowl.net sleepyowl.net. 600 IN A 78.31.70.238 ;; SERVER: 192.168.51.254#53(192.168.51.254)O roteador 192.168.51.254 respondeu e é responsável pela entrada do A. Pouca entrada pode ser requerida e o servidor de DNS pode selecionar com @:
# dig MX google.com # dig @127.0.0.1 NS sun.com # Para teste o local do servidor # dig @204.97.212.10 NS MX heise.de # Consulta externa do servidor # dig AXFR @ns1.xname.org cb.vu # Obtenha a zona cheia(zona de transferência)O programa da máquina também é poderoso.
# host -t MX cb.vu # Obtenha o mail MX de entrada # host -t NS -T sun.com # Obtenha o NS da conexão TCP. # host -a sleepyowl.net # Obtenha qualquer coisa
dig, host e
nslookup: # dig -x 78.31.70.238 # host 78.31.70.238 # nslookup 78.31.70.238
78.31.70.238 sleepyowl.net sleepyowlA prioridade entre as máquinas e as consultas dns, a ordem das consultas de resolução de nomes, podem ser configuradas no
/etc/nsswitch.conf e /etc/host.conf. O
arquivo existente do Windows, é normalmente no: C:\WINDOWS\SYSTEM32\DRIVERS\ETC
# dhcpcd -n eth0 # Provocar uma renovação( não é sempre funciona) # dhcpcd -k eth0 # lançamento e encerramentoO arrendamento com a total informação são armazenadas no:
/var/lib/dhcpcd/dhcpcd-eth0.info
# dhclient bge0O arrendamento com a total informação são armazenados no:
/var/db/dhclient.leases.bge0Usa
/etc/dhclient.confpara preceder as opções ou forçar as diferentes opções:
# cat /etc/dhclient.conf
interface "rl0" {
prepend domain-name-servers 127.0.0.1;
default domain-name "sleepyowl.net";
supersede domain-name "sleepyowl.net";
}
ipconfig:
# ipconfig /renew # renova todos os adaptadores # ipconfig /renew LAN # renew the adapter named "LAN" # ipconfig /release WLAN # release the adapter named "WLAN"Sim isto é uma boa idéia para renomear seu adaptador com simples nomes!
# tcpdump -nl -i bge0 not port ssh and src \(192.168.16.121 or 192.168.16.54\) # tcpdump -n -i eth1 net 192.168.16.121 # select to/from a single IP # tcpdump -n -i eth1 net 192.168.16.0/24 # select traffic to/from a network # tcpdump -l > dump && tail -f dump # Buffered output # tcpdump -i rl0 -w traffic.rl0 # Write traffic headers in binary file # tcpdump -i rl0 -s 0 -w traffic.rl0 # Write traffic + payload in binary file # tcpdump -r traffic.rl0 # Read from file (also for ethereal # tcpdump port 80 # The two classic commands # tcpdump host google.com # tcpdump -i eth0 -X port \(110 or 143\) # Check if pop or imap is secure # tcpdump -n -i eth0 icmp # Only catch pings # tcpdump -i eth0 -s 0 -A port 80 | grep GET # -s 0 for full packet -A for ASCIIAdiciona importante opções:
-A Imprime cada pacotes na limpeza do texto (sem
cabeçalho)-X Imprime pacotes em hex e ASCII-l Faça a linha de saída do buffer-D Imprime todas as interfaces disponíveis# nmap cb.vu # scans todas portas reservadas TCP na máquina # nmap -sP 192.168.16.0/24 # Procura IP de fora e são usados pela máquina na máquina 0/24 # nmap -sS -sV -O cb.vu # Faz a descrição SYN scan com a versão e SO detectadas PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 3.8.1p1 FreeBSD-20060930 (protocol 2.0) 25/tcp open smtp Sendmail smtpd 8.13.6/8.13.6 80/tcp open http Apache httpd 2.0.59 ((FreeBSD) DAV/2 PHP/4. [...] Running: FreeBSD 5.X Uptime 33.120 days (since Fri Aug 31 11:41:04 2007)Outro padrão mais usados são as ferramentas
hping (www.hping.org) um pacote
IP assembler/analyzer e fping (fping.sourceforge.net). fping pode checar
multiplos rund-robin fashion. # tc qdisc add dev eth0 root tbf rate 480kbit latency 50ms burst 1540 # tc -s qdisc ls dev eth0 # Status # tc qdisc del dev eth0 root # Delete the queue # tc qdisc change dev eth0 root tbf rate 220kbit latency 50ms burst 1540
dummynet tráfego afiado que são configurados
ipfw. Tubos são usados para aumentar seus limites da largura da banda na única
do[K|M]{bit/s|Byte/s}, 0 meios ilimitados. Usando igual ao número do tubo reconfigurará
isto. Por exemplo o limite do upload da largura da banda para 500 Kbit. # kldload dummynet # carrega os módulos se necessário # ipfw pipe 1 config bw 500Kbit/s # cria um tubo com limitado pela largura da banda # ipfw add pipe 1 ip from me to any # diverte todos os upload também pelo tubo
tc para otimizar VoIP. Veja o total
exemplo no voip-info.org ou www.howtoforge.com. Suposto VoIP usados udp na porta 10000:11024 e dispositivos
eth0 (também poderia ser ppp0 ou assim). Seguindo os comandos define o QoS para as filas
das árvores e força o tráfego VoIP para as filas The following commands com
QoS0x1e (todos os bits). O padrão do fluxo em 3 filas e QoS
Mínimo-atraso fluxo em 2 filas.
# tc qdisc add dev eth0 root handle 1: prio priomap 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 0 # tc qdisc add dev eth0 parent 1:1 handle 10: sfq # tc qdisc add dev eth0 parent 1:2 handle 20: sfq # tc qdisc add dev eth0 parent 1:3 handle 30: sfq # tc filter add dev eth0 protocol ip parent 1: prio 1 u32 \ match ip dport 10000 0x3C00 flowid 1:1 # usa a faixa de portas para os servidores match ip dst 123.23.0.1 flowid 1:1 # e/ou usa IP do servidorStatus and remove with
# tc -s qdisc ls dev eth0 # status da fila # tc qdisc del dev eth0 root # deleta todos QoS
# 2^13 (8192) < 10000 < 2^14 (16384) # finalizando é 2^14 = 16384 # echo "obase=16;(2^14)-1024" | bc # mask is 0x3C00
# ipfw pipe 1 config bw 500Kbit/s # ipfw queue 1 config pipe 1 weight 100 # ipfw queue 2 config pipe 1 weight 10 # ipfw queue 3 config pipe 1 weight 1 # ipfw add 10 queue 1 proto udp dst-port 10000-11024 # ipfw add 11 queue 1 proto udp dst-ip 123.23.0.1 # e/ou usa o IP do servidor # ipfw add 20 queue 2 dsp-port ssh # ipfw add 30 queue 3 from me to any # reinicia todosStatus e remove com
# ipfw list # status das regras # ipfw pipe list # status do tubo # ipfw flush # deleta todas as regras por padrão
# ypwhich # Obtem a conexão NIS do servidor de nomes # domainname # Configura o nome do domínio NIS # ypcat group # Mostra o grupo do servidor NIS # cd /var/yp && make # Reconstrói o yp banco de dados # rpcinfo -p servername # Relatório de serviço RPC do servidorEstá ypbind executando?
# ps auxww | grep ypbind /usr/sbin/ypbind -s -m -S servername1,servername2 # FreeBSD /usr/sbin/ypbind # Linux # yppoll passwd.byname Mapeia o passwd.byname têm outro número 1190635041. Seg Sep 24 13:57:21 2007 O serviço master é servername.domain.net.
# cat /etc/yp.conf ypserver nomeservidor domain domain.net broadcast
netcat em vez de nc. Também veja um
comando similar socat.
server# tar -cf - -C VIDEO_TS . | nc -l -p 4444 # Diretório tar na porta do servidor 4444 client# nc 192.168.1.1 4444 | tar xpf - -C VIDEO_TS # Puxa o arquivo na porta 4444 server# cat largefile | nc -l 5678 # O único arquivo client# nc 192.168.1.1 5678 > largefile # Puxa o único arquivo server# dd if=/dev/da0 | nc -l 4444 # Imagem da partição client# nc 192.168.1.1 4444 | dd of=/dev/da0 # Puxa a partição para o clone client# nc 192.168.1.1 4444 | dd of=da0.img # Puxa a partição para o arquivo
# nc -lp 4444 -e /bin/bash # Fornece um shell remoto (servidor clandestino) # nc -lp 4444 -e cmd.exe # shell remoto para Windows
# while true; do nc -l -p 80 < unixtoolbox.xhtml; done
alice# nc -lp 4444 bob # nc 192.168.1.1 4444
Chave Pública | Fingerprint | SCP | Tunelamento
# mkdir -p /home/USER/.ssh
~/.ssh/id_dsa is the
private key, ~/.ssh/id_dsa.pub é chave pública.~/.ssh/authorized_keys2 em sua casa no servidor.# ssh-keygen -t dsa -N '' # cat ~/.ssh/id_dsa.pub | ssh you@host-server "cat - >> ~/.ssh/authorized_keys2"
# cd ~/.ssh # ssh-keygen -i -f keyfilename.pub >> authorized_keys2
# scp .ssh/puttykey.pub [email protected]:.ssh/
# cd ~/.ssh # ssh-keygen -i -f puttykey.pub >> authorized_keys2
ssh-keygen -l para obter o fingerprint (no servidor):
# ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key.pub # Para chave RSA 2048 61:33:be:9b:ae:6c:36:31:fd:83:98:b7:99:2d:9f:cd /etc/ssh/ssh_host_rsa_key.pub # ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key.pub # Para DSA (padrão) 2048 14:4a:aa:d9:73:25:46:6d:0a:48:35:c7:f4:16:d4:ee /etc/ssh/ssh_host_dsa_key.pubAgora o cliente se conectar a esse servidor, pode verificar que ele está se conectando ao servidor direito:
# ssh linda A autenticação da máquina 'linda (192.168.16.54)' não pode ser estabelecida. Chave DSA fingerprint é 14:4a:aa:d9:73:25:46:6d:0a:48:35:c7:f4:16:d4:ee. Você tem certeza que deseja continuar a conexão (sim/não)? sim
# scp file.txt host-two:/tmp # scp joe@host-two:/www/*.html /www/tmp # scp -r joe@host-two:/www /www/tmpNo Konqueror ou Midnight Commander isso é possível para o acesso do sistema remoto com o endereço fish://user@porta. Entretanto a implementação é muito lenta.
# ssh -L localport:desthost:destport user@gate # desthost como pode ser visto a partir do portão # ssh -R destport:desthost:localport user@gate # porta local encaminha para o seu destino # desthost: localport como pode ser visto a partir do cliente do início do túnel # ssh -X user@gate # Para forçar encaminhamento XEste conectará na porta e encaminhará a porta local para a máquina desthost: destport. Nota desthost é a máquina de destino como pode ser visto pela porta, então se a conexão é para a porta, então o desthost é o localhost. Mais do que uma porta para o encaminhamento é possível.
# ssh -L 2401:localhost:2401 -L 8080:localhost:80 usuario@porta
# ssh -L 139:smbserver:139 -L 3388:smbserver:3389 usuario@portaO compartilhamento SMB pode agora ser acessado com \\127.0.0.1\, mas somente se o local do compartilhamento desabilitado, porque o local do compartilhamento é ouvido na porta 139.
# ssh -R 2022:localhost:22 usuario@porta # encaminha o cliente 22 para a porta: 2022
No cliente cliadmin (da máquina da porta):
# ssh -L 3022:localhost:2022 admin@porta # encaminha o cliente 3022 para a porta:2022
Agora o administrador pode ligar diretamente para o cliente cliusuario com: # ssh -p 3022 admin@localhost # local:3022 -> porta:2022 -> cliente:22
# ssh -R 15900:localhost:5900 user@gateOn client cliadmin (from host to gate):
# ssh -L 5900:localhost:15900 admin@gateAgora o administrador pode conectar diretamente ao cliente VNC com:
# vncconnect -display :0 localhost
cliente># ssh -L5678:localhost:5678 máquina1 # 5678 é uma porta arbitraria para o túnel maquina_1># ssh -L5678:localhost:5678 máquina2 # sequência 5678 da máquina1 para a máquina2 maquina_2># ssh -L5678:localhost:22 servidor # No final do túnel na porta 22 no servidor
# ssh -p 5678 localhost # conecta diretamente do cliente para o servidor # scp -P 5678 myfile localhost:/tmp/ # ou copia o arquivo diretamente utilizando o túnel # rsync -e 'ssh -p 5678' myfile localhost:/tmp/ # ou rsync o arquivo diretamente para o servidor
-L or -R
túneis em uma linha. #!/bin/sh COMMAND="ssh -N -f -g -R 3022:localhost:22 [email protected]" pgrep -f -x "$COMMAND" > /dev/null 2>&1 || $COMMAND exit 0
1 * * * * colin /home/colin/port_forward.sh # crontab entrada (aqui a cada hora)
PermitRootLogin yes PermitTunnel yes
cli># ssh -w5:5 root@hserver srv># ifconfig tun5 10.0.1.1 netmask 255.255.255.252 # Executada no shell do servidor
cli># ssh -w5:5 root@hserver srv># ifconfig tun5 10.0.1.1 10.0.1.2 # Executada no shell do servidor
cli># ifconfig tun5 10.0.1.2 netmask 255.255.255.252 # Cliente é um Linux cli># ifconfig tun5 10.0.1.2 10.0.1.1 # Cliente é um FreeBSDOs dois hosts estão conectados de forma transparente e podem se comunicar com qualquer protocolo de camada 3/4 usando os endereços IP do túnel.
gatewayA># ssh -w5:5 root@gateB gatewayB># ifconfig tun5 10.0.1.1 netmask 255.255.255.252 # Executada no shell do GatewayB gatewayB># route add -net 192.168.51.0 netmask 255.255.255.0 dev tun5 gatewayB># echo 1 > /proc/sys/net/ipv4/ip_forward # Somente necessário se o gateway não for padrão gatewayB># iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
gatewayA># ssh -w5:5 root@gateB # Cria o dispositivo tun5 gatewayB># ifconfig tun5 10.0.1.1 10.0.1.2 # Executada no shell do GatewayB gatewayB># route add 192.168.51.0/24 10.0.1.2 gatewayB># sysctl net.inet.ip.forwarding=1 # Somente necessário se o gateway não for padrão gatewayB># natd -s -m -u -dynamic -n fxp0 # veja NAT gatewayA># sysctl net.inet.ip.fw.enable=1
gatewayA># ifconfig tun5 10.0.1.2 netmask 255.255.255.252 gatewayA># route add -net 192.168.16.0 netmask 255.255.255.0 dev tun5 gatewayA># echo 1 > /proc/sys/net/ipv4/ip_forward gatewayA># iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
gatewayA># ifconfig tun5 10.0.1.2 10.0.1.1 gatewayA># route add 192.168.16.0/24 10.0.1.2 gatewayA># sysctl net.inet.ip.forwarding=1 gatewayA># natd -s -m -u -dynamic -n fxp0 # veja NAT gatewayA># sysctl net.inet.ip.fw.enable=1Agora as duas redes privadas estão conectadas transparentemente via VPN SSH. O NAT soemten é necessário se os gateways não forem o padrão da rede. Neste caso os clientes não sabem para onde encaminhar a resposta,e o nat deverá ser ativado.
# rsync -a /home/colin/ /backup/colin/ # modo "arquivo". manter o mesmo # rsync -a /var/ /var_bak/ # rsync -aR --delete-during /home/user/ /backup/ # utilização relativa (veja abaixo)Mesmo que a anterior, porém sobre a rede com com compressão. O Rsync usa o SSH por padrão para o transporte e usará as chaves ssh se for definido. Use ":" como o SCP. Uma típica cópia remota:
# rsync -axSRzv /home/user/ user@server:/backup/user/ # Cópia remota # rsync -a 'user@server:My\ Documents' My\ Documents # Simula a cópia para uma shell remotaExcluir qualquer diretório tmp dentro de /home/user/ e manter a hierarquia de pastas relativa, que o diretório remoto terá a estrutura /backup/home/user/. Isto é tipicamente usado para backups.
# rsync -azR --exclude=tmp/ /home/user/ user@server:/backup/Usa a porta 20022 para a conexão ssh:
# rsync -az -e 'ssh -p 20022' /home/colin/ user@server:/backup/colin/Usando o daemon rsync (usado com "::") é muito rápido, porém não encriptografados por ssh. A localização do /backup é definido pela configuração em /etc/rsyncd.conf. A variável RSYNC_PASSWORD pode ser ajustado para evitar a necessidade de digitar a senha manualmente.
# rsync -axSRz /home/ ruser@hostname::rmodule/backup/
# rsync -axSRz ruser@hostname::rmodule/backup/ /home/ # Para copiar de volta
Algumas opções importantes:-a, --archive modo arquivo; mesmo que -rlptgoD
(sem -H)-r, --recursive recursivo em diretórios-R, --relative usar nome de diretórios
relativo-H, --hard-links preserva os links-S, --sparse manipula os arquivos de forma
eficiente-x, --one-file-system não atravessa o limite
do sistema de arquivos --exclude=PATTERN Exclui os arquivos
padrões --delete-during exclui receptor durante xfer,
não antes --delete-after exclui receptor após a
transferência, não antesrsync e
ssh estão disponíveis no shell do Windows.# ssh-keygen -t dsa -N '' # Cria a chave pública e privada # rsync user@server:.ssh/authorized_keys2 . # Copia o arquivo localmente do server # cat id_dsa.pub >> authorized_keys2 # Ou usar um editor para adicionar a chave # rsync authorized_keys2 user@server:.ssh/ # Copia o arquivo de volta para o server # del authorized_keys2 # Remove a cópia localAgora teste com (em uma linha):
rsync -rv "/cygdrive/c/Documents and Settings/%USERNAME%/My Documents/" \ 'user@server:My\ Documents/'
@ECHO OFF REM rsync o diretório My Documents SETLOCAL SET CWRSYNCHOME=C:\PROGRAM FILES\CWRSYNC SET CYGWIN=nontsec SET CWOLDPATH=%PATH% REM descomente a linha seguinte, se usar cygwin SET PATH=%CWRSYNCHOME%\BIN;%PATH% echo Pressione Control-C para Abortar rsync -av "/cygdrive/c/Documents and Settings/%USERNAME%/My Documents/" \ 'user@server:My\ Documents/' pause
# sudo /etc/init.d/dhcpd restart # Run the rc script as root # sudo -u sysadmin whoami # Run cmd as an other user
/etc/sudoers and must only be edited with visudo. The basic syntax is (the lists are comma separated):
user hosts = (runas) commands # In /etc/sudoers
users one or more users or %group (like %wheel) to gain the rightshosts list of hosts (or ALL)runas list of users (or ALL) that the command rule can be run as. It is enclosed in ( )!commands list of commands (or ALL) that will be run as root or as (runas)# cat /etc/sudoers # Host aliases are subnets or hostnames. Host_Alias DMZ = 212.118.81.40/28 Host_Alias DESKTOP = work1, work2 # User aliases are a list of users which can have the same rights User_Alias ADMINS = colin, luca, admin User_Alias DEVEL = joe, jack, julia Runas_Alias DBA = oracle,pgsql # Command aliases define the full path of a list of commands Cmnd_Alias SYSTEM = /sbin/reboot,/usr/bin/kill,/sbin/halt,/sbin/shutdown,/etc/init.d/ Cmnd_Alias PW = /usr/bin/passwd [A-z]*, !/usr/bin/passwd root # Not root pwd! Cmnd_Alias DEBUG = /usr/sbin/tcpdump,/usr/bin/wireshark,/usr/bin/nmap
# The actual rules root,ADMINS ALL = (ALL) NOPASSWD: ALL # ADMINS can do anything w/o a password. DEVEL DESKTOP = (ALL) NOPASSWD: ALL # Developers have full right on desktops DEVEL DMZ = (ALL) NOPASSWD: DEBUG # Developers can debug the DMZ servers. # User sysadmin can mess around in the DMZ servers with some commands. sysadmin DMZ = (ALL) NOPASSWD: SYSTEM,PW,DEBUG sysadmin ALL,!DMZ = (ALL) NOPASSWD: ALL # Can do anything outside the DMZ. %dba ALL = (DBA) ALL # Group dba can run as database user. # anyone can mount/unmount a cd-rom on the desktop machines ALL DESKTOP = NOPASSWD: /sbin/mount /cdrom,/sbin/umount /cdrom
# openssl aes-128-cbc -salt -in file -out file.aes # openssl aes-128-cbc -d -salt -in file.aes -out fileNote that the file can of course be a tar archive.
# tar -cf - directory | openssl aes-128-cbc -salt -out directory.tar.aes # Encrypt # openssl aes-128-cbc -d -salt -in directory.tar.aes | tar -x -f - # Decrypt
# tar -zcf - directory | openssl aes-128-cbc -salt -out directory.tar.gz.aes # Encrypt # openssl aes-128-cbc -d -salt -in directory.tar.gz.aes | tar -xz -f - # Decrypt
# gpg -c file # Encrypt file with password # gpg file.gpg # Decrypt file (optionally -o otherfile)
# gpg --gen-key # This can take a long time
The keys are stored in ~/.gnupg/ on Unix, on Windows they are typically stored in~/.gnupg/pubring.gpg # Contains your public keys and all others imported ~/.gnupg/secring.gpg # Can contain more than one private keyShort reminder on most used options:
# gpg -e -r 'Your Name' file # Encrypt with your public key # gpg -o file -d file.gpg # Decrypt. Use -o or it goes to stdout
# gpg -a -o alicekey.asc --export 'Alice' # Alice exported her key in ascii file. # gpg --send-keys --keyserver subkeys.pgp.net KEYID # Alice put her key on a server. # gpg --import alicekey.asc # You import her key into your pubring. # gpg --search-keys --keyserver subkeys.pgp.net 'Alice' # or get her key from a server.Once the keys are imported it is very easy to encrypt or decrypt a file:
# gpg -e -r 'Alice' file # Encrypt the file for Alice. # gpg -d file.gpg -o file # Decrypt a file encrypted by Alice for you.
# gpg --list-keys # list public keys and see the KEYIDS The KEYID follows the '/' e.g. for: pub 1024D/D12B77CE the KEYID is D12B77CE # gpg --gen-revoke 'Your Name' # generate revocation certificate # gpg --list-secret-keys # list private keys # gpg --delete-keys NAME # delete a public key from local key ring # gpg --delete-secret-key NAME # delete a secret key from local key ring # gpg --fingerprint KEYID # Show the fingerprint of the key # gpg --edit-key KEYID # Edit key (e.g sign or add/del email)
Linux with LUKS | Linux dm-crypt only | FreeBSD GELI | FBSD pwd only
There are (many) other alternative methods to encrypt disks, I only show here the methods I know and use. Keep in mind that the security is only good as long the OS has not been tempered with. An intruder could easily record the password from the keyboard events. Furthermore the data is freely accessible when the partition is attached and will not prevent an intruder to have access to it in this state.dm-crypt (device-mapper) facility available on the 2.6 kernel. In this example, lets encrypt the partition /dev/sdc1, it could be however any other partition or disk, or USB or a file based partition created with losetup. In this case we would use /dev/loop0. See file image partition. The device mapper uses labels to identify a partition. We use sdc1 in this example, but it could be any string.
# cryptsetup --help, if nothing about LUKS shows up, use the instructions below Without LUKS. First create a partition if necessary: fdisk /dev/sdc.
# dd if=/dev/urandom of=/dev/sdc1 # Optional. For paranoids only (takes days) # cryptsetup -y luksFormat /dev/sdc1 # This destroys any data on sdc1 # cryptsetup luksOpen /dev/sdc1 sdc1 # mkfs.ext3 /dev/mapper/sdc1 # create ext3 file system # mount -t ext3 /dev/mapper/sdc1 /mnt # umount /mnt # cryptsetup luksClose sdc1 # Detach the encrypted partition
# cryptsetup luksOpen /dev/sdc1 sdc1 # mount -t ext3 /dev/mapper/sdc1 /mnt
# umount /mnt # cryptsetup luksClose sdc1
# cryptsetup -y create sdc1 /dev/sdc1 # or any other partition like /dev/loop0 # dmsetup ls # check it, will display: sdc1 (254, 0) # mkfs.ext3 /dev/mapper/sdc1 # This is done only the first time! # mount -t ext3 /dev/mapper/sdc1 /mnt # umount /mnt/ # cryptsetup remove sdc1 # Detach the encrypted partitionDo exactly the same (without the mkfs part!) to re-attach the partition. If the password is not correct, the mount command will fail. In this case simply remove the map sdc1 (
cryptsetup remove sdc1) and create it again.
gbde and geli. I now use geli because it is faster and also uses the crypto device for hardware acceleration. See The FreeBSD handbook Chapter 18.6http://www.freebsd.org/handbook/disks-encrypting.html for all the details. The geli module must be loaded or compiled into the kernel:
options GEOM_ELI device crypto # or as module: # echo 'geom_eli_load="YES"' >> /boot/loader.conf # or do: kldload geom_eli
/root/ad1.key to attach the partition. The master key is stored inside the partition and is not visible. See below for typical USB or file based image.
# dd if=/dev/random of=/root/ad1.key bs=64 count=1 # this key encrypts the mater key # geli init -s 4096 -K /root/ad1.key /dev/ad1 # -s 8192 is also OK for disks # geli attach -k /root/ad1.key /dev/ad1 # DO make a backup of /root/ad1.key # dd if=/dev/random of=/dev/ad1.eli bs=1m # Optional and takes a long time # newfs /dev/ad1.eli # Create file system # mount /dev/ad1.eli /mnt
# geli attach -k /root/ad1.key /dev/ad1
# fsck -ny -t ffs /dev/ad1.eli # In doubt check the file system
# mount /dev/ad1.eli /mnt
# umount /mnt # geli detach /dev/ad1.eli
# grep geli /etc/rc.conf geli_devices="ad1" geli_ad1_flags="-k /root/ad1.key" # grep geli /etc/fstab /dev/ad1.eli /home/private ufs rw 0 0
/cryptedfile of 1 GB.
# dd if=/dev/zero of=/cryptedfile bs=1M count=1000 # 1 GB file # mdconfig -at vnode -f /cryptedfile # geli init /dev/md0 # encrypts with password only # geli attach /dev/md0 # newfs -U -m 0 /dev/md0.eli # mount /dev/md0.eli /mnt # umount /dev/md0.eli # geli detach md0.eliIt is now possible to mount this image on an other system with the password only.
# mdconfig -at vnode -f /cryptedfile # geli attach /dev/md0 # mount /dev/md0.eli /mnt
[ CA_default ] dir = /usr/local/certs/CA # Where everything is kept certs = $dir/certs # Where the issued certs are kept crl_dir = $dir/crl # Where the issued crl are kept database = $dir/index.txt # database index file.Make sure the directories exist or create them
# mkdir -p /usr/local/certs/CA
# cd /usr/local/certs/CA
# mkdir certs crl newcerts private
# echo "01" > serial # Only if serial does not exist
# touch index.txt
If you intend to get a signed certificate from a vendor, you only need a certificate signing request (CSR). This CSR will then be signed by the vendor for a limited time (e.g. 1 year).
# openssl req -new -x509 -days 730 -config /etc/ssl/openssl.cnf \ -keyout CA/private/cakey.pem -out CA/cacert.pem
-nodes.
# openssl req -new -keyout newkey.pem -out newreq.pem \
-config /etc/ssl/openssl.cnf
# openssl req -nodes -new -keyout newkey.pem -out newreq.pem \
-config /etc/ssl/openssl.cnf # No encryption for the key
Keep this created CSR (newreq.pem) as it can be signed again at the next renewal, the signature onlt will limit the validity of the certificate. This process also created the private key newkey.pem.
# cat newreq.pem newkey.pem > new.pem # openssl ca -policy policy_anything -out servernamecert.pem \ -config /etc/ssl/openssl.cnf -infiles new.pem # mv newkey.pem servernamekey.pemNow servernamekey.pem is the private key and servernamecert.pem is the server certificate.
-----BEGIN RSA PRIVATE KEY----- MIICXQIBAAKBgQDutWy+o/XZ/[...]qK5LqQgT3c9dU6fcR+WuSs6aejdEDDqBRQ -----END RSA PRIVATE KEY----- -----BEGIN CERTIFICATE----- MIIERzCCA7CgAwIBAgIBBDANB[...]iG9w0BAQQFADCBxTELMAkGA1UEBhMCREUx -----END CERTIFICATE-----What we have now in the directory /usr/local/certs/:
# openssl x509 -text -in servernamecert.pem # View the certificate info # openssl req -noout -text -in server.csr # View the request info # openssl s_client -connect cb.vu:443 # Check a web server certificate
Server setup | CVS test | SSH tunneling | CVS usage
# mkdir -p /usr/local/cvs # setenv CVSROOT /usr/local/cvs # Set CVSROOT to the new location (local) # cvs init # Creates all internal CVS config files # cd /root # cvs checkout CVSROOT # Checkout the config files to modify them # cd CVSROOT edit config ( fine as it is) # cvs commit config cat >> writers # Create a writers file (optionally also readers) colin ^D # Use [Control][D] to quit the edit # cvs add writers # Add the file writers into the repository # cvs edit checkoutlist # cat >> checkoutlist writers ^D # Use [Control][D] to quit the edit # cvs commit # Commit all the configuration changesAdd a readers file if you want to differentiate read and write permissions Note: Do not (ever) edit files directly into the main cvs, but rather checkout the file, modify it and check it in. We did this with the file writers to define the write access.
cvspserver stream tcp nowait cvs /usr/bin/cvs cvs \ --allow-root=/usr/local/cvs pserverIt is a good idea to block the cvs port from the Internet with the firewall and use an ssh tunnel to access the repository remotely.
# htpasswd -cb passwd user1 password1 # -c creates the file
# htpasswd -b passwd user2 password2
Now add :cvs at the end of each line to tell the cvs server to change the user to cvs (or whatever your cvs server is running under). It looks like this:
# cat passwd user1:xsFjhU22u8Fuo:cvs user2:vnefJOsnnvToM:cvs
# cvs -d :pserver:[email protected]:/usr/local/cvs login Logging in to :pserver:[email protected]:2401/usr/local/cvs CVS password:
setenv CVSROOT string on a csh, tcsh shell, or with export CVSROOT=string on a sh, bash shell.
# setenv CVSROOT :pserver:<username>@<host>:/cvsdirectory For example: # setenv CVSROOT /usr/local/cvs # Used locally only # setenv CVSROOT :local:/usr/local/cvs # Same as above # setenv CVSROOT :ext:user@cvsserver:/usr/local/cvs # Direct access with SSH # setenv CVS_RSH ssh # for the ext access # setenv CVSROOT :pserver:[email protected]:/usr/local/cvs # network with pserverWhen the login succeeded one can import a new project into the repository: cd into your project root directory
cvs import <module name> <vendor tag> <initial tag> cvs -d :pserver:[email protected]:/usr/local/cvs import MyProject MyCompany STARTWhere MyProject is the name of the new project in the repository (used later to checkout). Cvs will import the current directory content into the new project.
# cvs -d :pserver:[email protected]:/usr/local/cvs checkout MyProject or # setenv CVSROOT :pserver:[email protected]:/usr/local/cvs # cvs checkout MyProject
# ssh -L2401:localhost:2401 colin@cvs_server # Connect directly to the CVS server. Or: # ssh -L2401:cvs_server:2401 colin@gateway # Use a gateway to reach the CVSon shell 2:
# setenv CVSROOT :pserver:colin@localhost:/usr/local/cvs # cvs login Logging in to :pserver:colin@localhost:2401/usr/local/cvs CVS password: # cvs checkout MyProject/src
# cvs import [options] directory-name vendor-tag release-tag # cd /devel # Must be inside the project to import it # cvs import myapp Company R1_0 # Release tag can be anything in one wordAfter a while a new directory "/devel/tools/" was added and it has to be imported too.
# cd /devel/tools # cvs import myapp/tools Company R1_0
# cvs co myapp/tools # Will only checkout the directory tools # cvs co -r R1_1 myapp # Checkout myapp at release R1_1 (is sticky) # cvs -q -d update -P # A typical CVS update # cvs update -A # Reset any sticky tag (or date, option) # cvs add newfile # Add a new file # cvs add -kb newfile # Add a new binary file # cvs commit file1 file2 # Commit the two files only # cvs commit -m "message" # Commit all changes done with a message
# cd /devel/project
# diff -Naur olddir newdir > patchfile # Create a patch from a directory or a file
# diff -Naur oldfile newfile > patchfile
# cd /devel/project # patch --dry-run -p0 < patchfile # Test the path without applying it # patch -p0 < patchfile # patch -p1 < patchfile # strip off the 1st level from the path
Server setup | SVN+SSH | SVN over http | SVN usage
Subversion (SVN)http://subversion.tigris.org/ is a version control system designed to be the successor of CVS (Concurrent Versions System). The concept is similar to CVS, but many shortcomings where improved. See also the SVN bookhttp://svnbook.red-bean.com/en/1.4/./home/svn/ must exist):
# svnadmin create --fs-type fsfs /home/svn/project1Now the access to the repository is made possible with:
file:// Direct file system access with the svn client with. This requires local permissions on the file system.svn:// or svn+ssh:// Remote access with the svnserve server (also over SSH). This requires local permissions on the file system (default port: 2690/tcp).http:// Remote access with webdav using apache. No local users are necessary for this method.# svn import /project1/ file:///home/svn/project1/trunk -m 'Initial import' # svn checkout file:///home/svn/project1The new directory "trunk" is only a convention, this is not required.
file:// with svn+ssh/hostname. For example:
# svn checkout svn+ssh://hostname/home/svn/project1As with the local file access, every user needs an ssh access to the server (with a local account) and also read/write access. This method might be suitable for a small group. All users could belong to a subversion group which owns the repository, for example:
# groupadd subversion # groupmod -A user1 subversion # chown -R root:subversion /home/svn # chmod -R 770 /home/svn
LoadModule dav_module modules/mod_dav.so
LoadModule dav_svn_module modules/mod_dav_svn.so
LoadModule authz_svn_module modules/mod_authz_svn.so # Only for access control
<Location /svn>
DAV svn
# any "/svn/foo" URL will map to a repository /home/svn/foo
SVNParentPath /home/svn
AuthType Basic
AuthName "Subversion repository"
AuthzSVNAccessFile /etc/apache2/svn.acl
AuthUserFile /etc/apache2/svn-passwd
Require valid-user
</Location>
The apache server needs full access to the repository:
# chown -R www:www /home/svnCreate a user with htpasswd2:
# htpasswd -c /etc/svn-passwd user1 # -c creates the file
# Default it read access. "* =" would be default no access [/] * = r [groups] project1-developers = joe, jack, jane # Give write access to the developers [project1:] @project1-developers = rw
import command. Import is also used to add a directory with its content to an existing project.
# svn help import # Get help for any command # Add a new directory (with content) into the src dir on project1 # svn import /project1/newdir http://host.url/svn/project1/trunk/src -m 'add newdir'
# svn co http://host.url/svn/project1/trunk # Checkout the most recent version # Tags and branches are created by copying # svn mkdir http://host.url/svn/project1/tags/ # Create the tags directory # svn copy -m "Tag rc1 rel." http://host.url/svn/project1/trunk \ http://host.url/svn/project1/tags/1.0rc1 # svn status [--verbose] # Check files status into working dir # svn add src/file.h src/file.cpp # Add two files # svn commit -m 'Added new class file' # Commit the changes with a message # svn ls http://host.url/svn/project1/tags/ # List all tags # svn move foo.c bar.c # Move (rename) files # svn delete some_old_file # Delete files
less | vi | mail | tar | dd | screen | find | Miscellaneous
less command displays a text document on the console. It is present on most installation.
# less unixtoolbox.xhtmlSome important commands are (^N stands for [control]-[N]):
: help if you are lost.nano and pico are usually available too and are easier (IMHO) to use.
mail command is a basic application to read and send email, it is usually installed. To send an email simply type "mail user@domain". The first line is the subject, then the mail content. Terminate and send the email with a single dot (.) in a new line. Example:
# mail [email protected] Subject: Your text is full of typos "For a moment, nothing happened. Then, after a second or so, nothing continued to happen." . EOT #This is also working with a pipe:
# echo "This is the mail body" | mail [email protected]This is also a simple way to test the mail server.
tar (tape archive) creates and extracts archives of file and directories. The archive .tar is uncompressed, a compressed archive has the extension .tgz or .tar.gz (zip) or .tbz (bzip2). Do not use absolute path when creating an archive, you probably want to unpack it somewhere else. Some typical commands are:
# cd / # tar -cf home.tar home/ # archive the whole /home directory (c for create) # tar -czf home.tgz home/ # same with zip compression # tar -cjf home.tbz home/ # same with bzip2 compressionOnly include one (or two) directories from a tree, but keep the relative structure. For example archive /usr/local/etc and /usr/local/www and the first directory in the archive should be local/.
# tar -C /usr -czf local.tgz local/etc local/www # tar -C /usr -xzf local.tgz # To untar the local dir into /usr # cd /usr; tar -xzf local.tgz # Is the same as above
# tar -tzf home.tgz # look inside the archive without extracting (list) # tar -xf home.tar # extract the archive here (x for extract) # tar -xzf home.tgz # same with zip compression (-xjf for bzip2 compression) # remove leading path gallery2 and extract into gallery # tar --strip-components 1 -zxvf gallery2.tgz -C gallery/ # tar -xjf home.tbz home/colin/file.txt # Restore a single file
# tar c dir/ | gzip | ssh user@remote 'dd of=dir.tgz' # arch dir/ and store remotely. # tar cvf - `find . -print` > backup.tar # arch the current directory. # tar -cf - -C /etc . | tar xpf - -C /backup/etc # Copy directories # tar -cf - -C /etc . | ssh user@remote tar xpf - -C /backup/etc # Remote copy. # tar -czf home.tgz --exclude '*.o' --exclude 'tmp/' home/
dd (disk dump or destroy disk or see the meaning of dd) is used to copy partitions and disks and for other copy tricks. Typical usage:
# dd if=<source> of=<target> bs=<byte size> conv=<conversion>Important conv options:
notrunc do not truncate the output file, all zeros will be written as zeros.noerror continue after read errors (e.g. bad blocks)sync pad every input block with Nulls to ibs-size# dd if=/dev/hda of=/dev/hdc bs=16065b # Copy disk to disk (same size) # dd if=/dev/sda7 of=/home/root.img bs=4096 conv=notrunc,noerror # Backup / # dd if=/home/root.img of=/dev/sda7 bs=4096 conv=notrunc,noerror # Restore / # dd bs=1M if=/dev/ad4s3e | gzip -c > ad4s3e.gz # Zip the backup # gunzip -dc ad4s3e.gz | dd of=/dev/ad0s3e bs=1M # Restore the zip # dd bs=1M if=/dev/ad4s3e | gzip | ssh eedcoba@fry 'dd of=ad4s3e.gz' # also remote # gunzip -dc ad4s3e.gz | ssh eedcoba@host 'dd of=/dev/ad0s3e bs=1M' # dd if=/dev/ad0 of=/dev/ad2 skip=1 seek=1 bs=4k conv=noerror # Skip MBR # This is necessary if the destination (ad2) is smaller.
dd will read every single block of the partition. In case of problems it is better to use the option conv=sync,noerror so dd will skip the bad block and write zeros at the destination. Accordingly it is important to set the block size equal or smaller than the disk block size. A 1k size seems safe, set it with bs=1k. If a disk has bad sectors and the data should be recovered from a partition, create an image file with dd, mount the image and copy the content to a new disk. With the option noerror, dd will skip the bad sectors and write zeros instead, thus only the data contained in the bad sectors will be lost.
# dd if=/dev/hda of=/dev/null bs=1m # Check for bad blocks # dd bs=1k if=/dev/hda1 conv=sync,noerror,notrunc | gzip | ssh \ # Send to remote root@fry 'dd of=hda1.gz bs=1k' # dd bs=1k if=/dev/hda1 conv=sync,noerror,notrunc of=hda1.img # Store into an image # mount -o loop /hda1.img /mnt # Mount the image # rsync -ax /mnt/ /newdisk/ # Copy on a new disk # dd if=/dev/hda of=/dev/hda # Refresh the magnetic state # The above is useful to refresh a disk. It is perfectly safe, but must be unmounted.
# dd if=/dev/zero of=/dev/hdc # Delete full disk # dd if=/dev/urandom of=/dev/hdc # Delete full disk better # kill -USR1 PID # View dd progress (Linux) # kill -INFO PID # View dd progress (FreeBSD)
# dd if=/dev/sda of=/mbr_sda.bak bs=512 count=1 # Backup the full MBR # dd if=/dev/zero of=/dev/sda bs=512 count=1 # Delete MBR and partition table # dd if=/mbr_sda.bak of=/dev/sda bs=512 count=1 # Restore the full MBR # dd if=/mbr_sda.bak of=/dev/sda bs=446 count=1 # Restore only the boot loader # dd if=/mbr_sda.bak of=/dev/sda bs=1 count=64 skip=446 seek=446 # Restore partition table
# screenWithin the screen session we can start a long lasting program (like top).
# topNow detach with Ctrl-a Ctrl-d. Reattach the terminal with:
# screen -R -DIn detail this means: If a session is running, then reattach. If necessary detach and logout remotely first. If it was not running create it and notify the user. Or:
# screen -xAttach to a running screen in a multi display mode. The console is thus shared among multiple users. Very useful for team work/debug!
-x (on BSD) -xdev (on Linux) Stay on the same file system (dev in fstab).-exec cmd {} \; Execute the command and replace {} with the full path-iname Like -name but is case insensitive-ls Display information about the file (like ls -la)-size n n is +-n (k M G T P)-cmin n File's status was last changed n minutes ago.# find . -type f ! -perm -444 # Find files not readable by all # find . -type d ! -perm -111 # Find dirs not accessible by all # find /home/user/ -cmin 10 -print # Files created or modified in the last 10 min. # find . -name '*.[ch]' | xargs grep -E 'expr' # Search 'expr' in this dir and below. # find / -name "*.core" | xargs rm # Find core dumps and delete them (also try core.*) # find / -name "*.core" -print -exec rm {} \; # Other syntax # Find images and create an archive, iname is not case sensitive. -r for append # find . \( -iname "*.png" -o -iname "*.jpg" \) -print -exec tar -rf images.tar {} \; # find . -type f -name "*.txt" ! -name README.txt -print # Exclude README.txt files # find /var/ -size +10M -exec ls -lh {} \; # Find large files > 10 MB # find /var/ -size +10M -ls # This is simpler # find . -size +10M -size -50M -print # find /usr/ports/ -name work -type d -print -exec rm -rf {} \; # Clean the ports # Find files with SUID; those file are vulnerable and must be kept secure # find / -type f -user root -perm -4000 -exec ls -l {} \;Be careful with xarg or exec as it might or might not honor quotings and can return wrong results when files or directories contain spaces. In doubt use "-print0 | xargs -0" instead of "| xargs". The option -print0 must be the last in the find command. See this nice mini tutorial for findhttp://www.hccfl.edu/pollock/Unix/FindCmd.htm.
# find . -type f | xargs ls -l # Will not work with spaces in names # find . -type f -print0 | xargs -0 ls -l # Will work with spaces in names # find . -type f -exec ls -l '{}' \; # Or use quotes '{}' with -exec
# which command # Show full path name of command # time command # See how long a command takes to execute # time cat # Use time as stopwatch. Ctrl-c to stop # set | grep $USER # List the current environment # cal -3 # Display a three month calendar # date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]] # date 10022155 # Set date and time # whatis grep # Display a short info on the command or word # whereis java # Search path and standard directories for word # setenv varname value # Set env. variable varname to value (csh/tcsh) # export varname="value" # set env. variable varname to value (sh/ksh/bash) # pwd # Print working directory # mkdir -p /path/to/dir # no error if existing, make parent dirs as needed # mkdir -p project/{bin,src,obj,doc/{html,man,pdf},debug/some/more/dirs} # rmdir /path/to/dir # Remove directory # rm -rf /path/to/dir # Remove directory and its content (force) # cp -la /dir1 /dir2 # Archive and hard link files instead of copy # cp -lpR /dir1 /dir2 # Same for FreeBSD # cp unixtoolbox.xhtml{,.bak} # Short way to copy the file with a new extension # mv /dir1 /dir2 # Rename a directory # ls -1 # list one file per line # history | tail -50 # Display the last 50 used commandsCheck file hashes with openssl. This is a nice alternative to the commands
md5sum or sha1sum (FreeBSD uses md5 and sha1) which are not always installed.
# openssl md5 file.tar.gz # Generate an md5 checksum from file # openssl sha1 file.tar.gz # Generate an sha1 checksum from file # openssl rmd160 file.tar.gz # Generate a RIPEMD-160 checksum from file
export http_proxy=http://proxy_server:3128 export ftp_proxy=http://proxy_server:3128
# rpm -qa # List installed packages (RH, SuSE, RPM based) # dpkg -l # Debian, Ubuntu # pkg_info # FreeBSD list all installed packages # pkg_info -W smbd # FreeBSD show which package smbd belongs to # pkginfo # Solaris
# rpm -i pkgname.rpm # install the package (RH, SuSE, RPM based) # rpm -e pkgname # Remove package
# apt-get update # First update the package lists # apt-get install emacs # Install the package emacs # dpkg --remove emacs # Remove the package emacs # dpkg -S file # find what package a file belongs to
# emerge --sync # First sync the local portage tree # emerge -u packagename # Install or upgrade a package # emerge -C packagename # Remove the package # revdep-rebuild # Repair dependencies
/cdrom/cdrom0.
# pkgadd -d <cdrom>/Solaris_9/Product SUNWgtar # pkgadd -d SUNWgtar # Add downloaded package (bunzip2 first) # pkgrm SUNWgtar # Remove the package
# pkg_add -r rsync # Fetch and install rsync. # pkg_delete /var/db/pkg/rsync-xx # Delete the rsync packageSet where the packages are fetched from with the
PACKAGESITE variable. For example:
# export PACKAGESITE=ftp://ftp.freebsd.org/pub/FreeBSD/ports/i386/packages/Latest/ # or ftp://ftp.freebsd.org/pub/FreeBSD/ports/i386/packages-6-stable/Latest/
/usr/ports/ is a collection of software ready to compile and install (see man ports). The ports are updated with the program portsnap.
# portsnap fetch extract # Create the tree when running the first time # portsnap fetch update # Update the port tree # cd /usr/ports/net/rsync/ # Select the package to install # make install distclean # Install and cleanup (also see man ports) # make package # Make a binary package of this port # pkgdb -F # Fix the package registry database
ldd and managed with ldconfig.
# ldd /usr/bin/rsync # List all needed runtime libraries # ldconfig -n /path/to/libs/ # Add a path to the shared libraries directories # ldconfig -m /path/to/libs/ # FreeBSD # LD_LIBRARY_PATH # The variable set the link library path
iconv can convert from
one encoding to an other.
# iconv -f <from_encoding> -t <to_encoding> <input_file>
# iconv -f ISO8859-1 -t UTF-8 -o file.input > file_utf8
# iconv -l # List known coded character sets
Without the -f option, iconv will use the local char-set, which is usually fine
if the document displays well.
dos2unix and unix2dos if you have them.
# sed 's/.$//' dosfile.txt > unixfile.txt # DOS to UNIX # awk '{sub(/\r$/,"");print}' dosfile.txt > unixfile.txt # DOS to UNIX # awk '{sub(/$/,"\r");print}' unixfile.txt > dosfile.txt # UNIX to DOSConvert Unix to DOS newlines within a Windows environment. Use sed or awk from mingw or cygwin.
# sed -n p unixfile.txt > dosfile.txt
# awk 1 unixfile.txt > dosfile.txt # UNIX to DOS (with a cygwin shell)
gs (GhostScript) to jpeg (or png) images for each page. Also much shorter with convert and mogrify (from ImageMagick or GraphicsMagick).
# gs -dBATCH -dNOPAUSE -sDEVICE=jpeg -r150 -dTextAlphaBits=4 -dGraphicsAlphaBits=4 \ -dMaxStripSize=8192 -sOutputFile=unixtoolbox_%d.jpg unixtoolbox.pdf # convert unixtoolbox.pdf unixtoolbox-%03d.png # convert *.jpeg images.pdf # Create a simple PDF with all pictures # convert image000* -resample 120x120 -compress JPEG -quality 80 images.pdf # mogrify -format png *.ppm # convert all ppm images to png formatGhostscript can also concatenate multiple pdf files into a single one. This only works well if the PDF files are "well behaved".
# gs -q -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=all.pdf \
file1.pdf file2.pdf ... # On Windows use '#' instead of '='
# mencoder -o videoout.avi -oac mp3lame -ovc lavc -srate 11025 \ -channels 1 -af-adv force=1 -lameopts preset=medium -lavcopts \ vcodec=msmpeg4v2:vbitrate=600 -mc 0 vidoein.AVISee sox for sound processing.
cdparanoiahttp://xiph.org/paranoia/ can save the audio tracks (FreeBSD port in audio/cdparanoia/), oggenc can encode in Ogg Vorbis format, lame converts to mp3.
# cdparanoia -B # Copy the tracks to wav files in current dir # lame -b 256 in.wav out.mp3 # Encode in mp3 256 kb/s # for i in *.wav; do lame -b 256 $i `basename $i .wav`.mp3; done # oggenc in.wav -b 256 out.ogg # Encode in Ogg Vorbis 256 kb/s
# lpr unixtoolbox.ps # Print on default printer # export PRINTER=hp4600 # Change the default printer # lpr -Php4500 #2 unixtoolbox.ps # Use printer hp4500 and print 2 copies # lpr -o Duplex=DuplexNoTumble ... # Print duplex along the long side # lpr -o PageSize=A4,Duplex=DuplexNoTumble ...
# lpq # Check the queue on default printer # lpq -l -Php4500 # Queue on printer hp4500 with verbose # lprm - # Remove all users jobs on default printer # lprm -Php4500 3186 # Remove job 3186. Find job nbr with lpq # lpc status # List all available printers # lpc status hp4500 # Check if printer is online and queue lengthSome devices are not postscript and will print garbage when fed with a pdf file. This might be solved with:
# gs -dSAFER -dNOPAUSE -sDEVICE=deskjet -sOutputFile=\|lpr file.pdfPrint to a PDF file even if the application does not support it. Use
gs on the print command instead of lpr.
# gs -q -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=/path/file.pdf
# psql -d template1 -U pgsql
> alter user pgsql with password 'pgsql_password'; # Use username instead of "pgsql"
createuser, dropuser, createdb and dropdb are convenient shortcuts equivalent to the SQL commands. The new user is bob with database bobdb ; use as root with pgsql the database super user:
# createuser -U pgsql -P bob # -P will ask for password # createdb -U pgsql -O bob bobdb # new bobdb is owned by bob # dropdb bobdb # Delete database bobdb # dropuser bob # Delete user bobThe general database authentication mechanism is configured in pg_hba.conf
$PGSQL_DATA_D/postgresql.conf specifies the address to bind to. Typically listen_addresses = '*' for Postgres 8.x.$PGSQL_DATA_D/pg_hba.conf defines the access control. Examples:
# TYPE DATABASE USER IP-ADDRESS IP-MASK METHOD host bobdb bob 212.117.81.42 255.255.255.255 password host all all 0.0.0.0/0 password
# pg_dump --clean dbname > dbname_sql.dump # psql dbname < dbname_sql.dumpBackup and restore all databases (including users):
# pg_dumpall --clean > full.dump # psql -f full.dump postgresIn this case the restore is started with the database postgres which is better when reloading an empty cluster.
# /etc/init.d/mysql stop
or
# killall mysqld
# mysqld --skip-grant-tables
# mysqladmin -u root password 'newpasswd'
# /etc/init.d/mysql start
# mysql -u root mysql mysql> UPDATE USER SET PASSWORD=PASSWORD("newpassword") where user='root'; mysql> FLUSH PRIVILEGES; # Use username instead of "root" mysql> quit
# mysql -u root mysql mysql> CREATE USER 'bob'@'localhost' IDENTIFIED BY 'pwd'; # create only a user mysql> CREATE DATABASE bobdb; mysql> GRANT ALL ON *.* TO 'bob'@'%' IDENTIFIED BY 'pwd'; # Use localhost instead of % # to restrict the network access mysql> DROP DATABASE bobdb; # Delete database mysql> DROP USER bob; # Delete user mysql> DELETE FROM mysql.user WHERE user='bob and host='hostname'; # Alt. command mysql> FLUSH PRIVILEGES;
/etc/my.cnf contains the IP address to bind to. Typically comment the line bind-address = out.
# mysql -u root mysql mysql> GRANT ALL ON bobdb.* TO bob@'xxx.xxx.xxx.xxx' IDENTIFIED BY 'PASSWORD'; mysql> REVOKE GRANT OPTION ON foo.* FROM bar@'xxx.xxx.xxx.xxx'; mysql> FLUSH PRIVILEGES; # Use 'hostname' or also '%' for full access
# mysqldump -u root -psecret --add-drop-database dbname > dbname_sql.dump # mysql -u root -psecret -D dbname < dbname_sql.dumpBackup and restore all databases:
# mysqldump -u root -psecret --add-drop-database --all-databases > full.dump # mysql -u root -psecret < full.dumpHere is "secret" the mysql root password, there is no space after -p. When the -p option is used alone (w/o password), the password is asked at the command prompt.
sqlite3 for a 3.x database.
# sqlite database.db .dump > dump.sql # dump # sqlite database.db < dump.sql # restore
sqlite database_v2.db .dump | sqlite3 database_v3.db
usrquota to the fstab mount options, for example:
/dev/sda2 /home reiserfs rw,acl,user_xattr,usrquota 1 1
# mount -o remount /home
# mount # Check if usrquota is active, otherwise reboot
Initialize the quota.user file with quotacheck.
# quotacheck -vum /home
# chmod 644 /home/aquota.user # To let the users check their own quota
Activate the quota either with the provided script (e.g. /etc/init.d/quotad on SuSE) or with quotaon:
quotaon -vu /homeCheck that the quota is active with:
quota -v
options QUOTAAs with Linux, add the quota to the fstab options (userquota, not usrquota):
/dev/ad0s1d /home ufs rw,noatime,userquota 2 2
# mount /home # To remount the partition
Enable disk quotas in /etc/rc.conf and start the quota.
# grep quotas /etc/rc.conf enable_quotas="YES" # turn on quotas on startup (or NO). check_quotas="YES" # Check quotas on startup (or NO). # /etc/rc.d/quota start
edquota for single users. A quota can be also duplicated to many users. The file structure is different between the quota implementations, but the principle is the same: the values of blocks and inodes can be limited. Only change the values of soft and hard. If not specified, the blocks are 1k. The grace period is set with edquota -t. For example:
# edquota -u colin
Disk quotas for user colin (uid 1007): Filesystem blocks soft hard inodes soft hard /dev/sda8 108 1000 2000 1 0 0
Quotas for user colin: /home: kbytes in use: 504184, limits (soft = 700000, hard = 800000) inodes in use: 1792, limits (soft = 0, hard = 0)
edquota -p is used to duplicate a quota to other users. For example to duplicate a reference quota to all users:
# edquota -p refuser `awk -F: '$3 > 499 {print $1}' /etc/passwd`
# edquota -p refuser user1 user2 # Duplicate to 2 users
quota (the file quota.user must be readable). Root can check all quotas.
# quota -u colin # Check quota for a user # repquota /home # Full report for the partition for all users
grep Pattern matchingsed Search and Replace strings or characterscut Print specific columns from a markersort Sort alphabetically or numericallyuniq Remove duplicate lines from a file# ifconfig | sed 's/ / /g' | cut -d" " -f1 | uniq | grep -E "[a-z0-9]+" | sort -r # ifconfig | sed '/.*inet addr:/!d;s///;s/ .*//'|sort -t. -k1,1n -k2,2n -k3,3n -k4,4nThe first character in the sed pattern is a tab. To write a tab on the console, use ctrl-v ctrl-tab.
# cmd 1> file # Redirect stdout to file. # cmd 2> file # Redirect stderr to file. # cmd 1>> file # Redirect and append stdout to file. # cmd &> file # Redirect both stdout and stderr to file. # cmd >file 2>&1 # Redirects stderr to stdout and then to file. # cmd1 | cmd2 # pipe stdout to cmd2 # cmd1 2>&1 | cmd2 # pipe stdout and stderr to cmd2Modify your configuration in ~/.bashrc (it can also be ~/.bash_profile). The following entries are useful, reload with ". .bashrc".
# in .bashrc bind '"\e[A"':history-search-backward # Use up and down arrow to search bind '"\e[B"':history-search-forward # the history. Invaluable! set -o emacs # Set emacs mode in bash (see below) set bell-style visible # Do not beep, inverse colors # Set a nice prompt like [user@host]/path/todir> PS1="\[\033[1;30m\][\[\033[1;34m\]\u\[\033[1;30m\]" PS1="$PS1@\[\033[0;33m\]\h\[\033[1;30m\]]\[\033[0;37m\]" PS1="$PS1\w\[\033[1;30m\]>\[\033[0m\]"
# To check the currently active aliases, simply type alias alias ls='ls -aF' # Append indicator (one of */=>@|) alias ll='ls -aFls' # Listing alias la='ls -all' alias ..='cd ..' alias ...='cd ../..' export HISTFILESIZE=5000 # Larger history export CLICOLOR=1 # Use colors (if possible) export LSCOLORS=ExGxFxdxCxDxDxBxBxExEx
# cmd >& file # Redirect both stdout and stderr to file. # cmd >>& file # Append both stdout and stderr to file. # cmd1 | cmd2 # pipe stdout to cmd2 # cmd1 |& cmd2 # pipe stdout and stderr to cmd2The settings for csh/tcsh are set in
~/.cshrc, reload with "source .cshrc". Examples:
# in .cshrc alias ls 'ls -aF' alias ll 'ls -aFls' alias la 'ls -all' alias .. 'cd ..' alias ... 'cd ../..' set prompt = "%B%n%b@%B%m%b%/> " # like user@host/path/todir> set history = 5000 set savehist = ( 6000 merge ) set autolist # Report possible completions with tab set visiblebell # Do not beep, inverse colors
# Bindkey and colors bindkey -e Select Emacs bindings # Use emacs keys to edit the command prompt bindkey -k up history-search-backward # Use up and down arrow to search bindkey -k down history-search-forward setenv CLICOLOR 1 # Use colors (if possible) setenv LSCOLORS ExGxFxdxCxDxDxBxBxExExThe emacs mode enables to use the emacs keys shortcuts to modify the command prompt line. This is extremely useful (not only for emacs users). The most used commands are:
Basics | Script example | awk | sed | Regular Expressions | useful commands
The Bourne shell (/bin/sh) is present on all Unix installations and scripts written in this language are (quite) portable;man 1 sh is a good reference.
MESSAGE="Hello World" # Assign a string PI=3.1415 # Assign a decimal number N=8 TWON=`expr $N * 2` # Arithmetic expression (only integers) TWON=$(($N * 2)) # Other syntax TWOPI=`echo "$PI * 2" | bc -l` # Use bc for floating point operations ZERO=`echo "c($PI/4)-sqrt(2)/2" | bc -l`The command line arguments are
$0, $1, $2, ... # $0 is the command itself $# # The number of arguments $* # All arguments (also $@)
$$ # The current process ID $? # exit status of last command command if [ $? != 0 ]; then echo "command failed" fi mypath=`pwd` mypath=${mypath}/file.txt echo ${mypath##*/} # Display the filename only echo ${mypath%%.*} # Full path without extention var2=${var:=string} # Use var if set, otherwise use string # assign string to var and then to var2.
for file in `ls` do echo $file done count=0 while [ $count -lt 5 ]; do echo $count sleep 1 count=$(($count + 1)) done myfunction() { find . -type f -name "*.$1" -print # $1 is first argument of the function } myfunction "txt"
MYHOME=/home/colin cat > testhome.sh << _EOF # All of this goes into the file testhome.sh if [ -d "$MYHOME" ] ; then echo $MYHOME exists else echo $MYHOME does not exist fi _EOF sh testhome.sh
#!/bin/sh # This script creates a book in pdf format ready to print on a duplex printer if [ $# -ne 1 ]; then # Check the argument echo 1>&2 "Usage: $0 HtmlFile" exit 1 # non zero exit if error fi file=$1 # Assign the filename fname=${file%.*} # Get the name of the file only fext=${file#*.} # Get the extension of the file prince $file -o $fname.pdf # from www.princexml.com pdftops -paper A4 -noshrink $fname.pdf $fname.ps # create postscript booklet cat $fname.ps |psbook|psnup -Pa4 -2 |pstops -b "2:0,1U(21cm,29.7cm)" > $fname.book.ps ps2pdf13 -sPAPERSIZE=a4 -sAutoRotatePages=None $fname.book.ps $fname.book.pdf # use #a4 and #None on Windows! exit 0 # exit 0 means successful
awk '{ print $2, $1 }' file # Print and inverse first two columns
awk '{printf("%5d : %s\n", NR,$0)}' file # Add line number left aligned
awk '{print FNR "\t" $0}' files # Add line number right aligned
awk NF test.txt # remove blank lines (same as grep '.')
awk 'length > 80' # print line longer than 80 char)
sed 's/string1/string2/g' # Replace string1 with string2 sed -i 's/wroong/wrong/g' *.txt # Replace a recurring word with g sed 's/\(.*\)1/\12/g' # Modify anystring1 to anystring2 sed '/<p>/,/<\/p>/d' t.xhtml # Delete lines that start with <p> # and end with </p> sed '/ *#/d; /^ *$/d' # Remove comments and blank lines sed 's/[ \t]*$//' # Remove trailing spaces (use tab as \t) sed 's/^[ \t]*//;s/[ \t]*$//' # Remove leading and trailing spaces sed 's/[^*]/[&]/' # Enclose first char with [] top->[t]op sed = file | sed 'N;s/\n/\t/' > file.num # Number lines on a file
[\^$.|?*+() # special characters any other will match themselves \ # escapes special characters and treat as literal * # repeat the previous item zero or more times . # single character except line break characters .* # match zero or more characters ^ # match at the start of a line/string $ # match at the end of a line/string .$ # match a single character at the end of line/string ^ $ # match line with a single space [^A-Z] # match any line beginning with any char from A to Z
sort -t. -k1,1n -k2,2n -k3,3n -k4,4n # Sort IPv4 ip addresses echo 'Test' | tr '[:lower:]' '[:upper:]' # Case conversion echo foo.bar | cut -d . -f 1 # Returns foo PID=$(ps | grep script.sh | grep bin | awk '{print $1}') # PID of a running script PID=$(ps axww | grep [p]ing | awk '{print $1}') # PID of ping (w/o grep pid) IP=$(ifconfig $INTERFACE | sed '/.*inet addr:/!d;s///;s/ .*//') # Linux IP=$(ifconfig $INTERFACE | sed '/.*inet /!d;s///;s/ .*//') # FreeBSD if [ `diff file1 file2 | wc -l` != 0 ]; then [...] fi # File changed? cat /etc/master.passwd | grep -v root | grep -v \*: | awk -F":" \ # Create http passwd '{ printf("%s:%s\n", $1, $2) }' > /usr/local/etc/apache2/passwd testuser=$(cat /usr/local/etc/apache2/passwd | grep -v \ # Check user in passwd root | grep -v \*: | awk -F":" '{ printf("%s\n", $1) }' | grep ^user$) :(){ :|:& };: # bash fork bomb. Will kill your machine tail +2 file > file2 # remove the first line from fileI use this little trick to change the file extension for many files at once. For example from .cxx to .cpp. Test it first without the
| sh at the end. You can also do this with the command rename if installed. Or with bash builtins.
# ls *.cxx | awk -F. '{print "mv "$0" "$1".cpp"}' | sh
# ls *.c | sed "s/.*/cp & &.$(date "+%Y%m%d")/" | sh # e.g. copy *.c to *.c.20080401
# rename .cxx .cpp *.cxx # Rename all .cxx to cpp
# for i in *.cxx; do mv $i ${i%%.cxx}.cpp; done # with bash builtins
strcpy(newstr,str) /* copy str to newstr */ expr1 ? expr2 : expr3 /* if (expr1) expr2 else expr3 */ x = (y > z) ? y : z; /* if (y > z) x = y; else x = z; */ int a[]={0,1,2}; /* Initialized array (or a[3]={0,1,2}; */ int a[2][3]={{1,2,3},{4,5,6}}; /* Array of array of ints */ int i = 12345; /* Convert in i to char str */ char str[10]; sprintf(str, "%d", i);
#include <stdio.h> main() { int number=42; printf("The answer is %i\n", number); }Compile with:
# gcc simple.c -o simple # ./simple The answer is 42
*pointer // Object pointed to by pointer &obj // Address of object obj obj.x // Member x of class obj (object obj) pobj->x // Member x of class pointed to by pobj // (*pobj).x and pobj->x are the same
#ifndef IPV4_H #define IPV4_H #include <string> namespace GenericUtils { // create a namespace class IPv4 { // class definition public: IPv4(); ~IPv4(); std::string IPint_to_IPquad(unsigned long ip);// member interface }; } //namespace GenericUtils #endif // IPV4_H
#include "IPv4.h" #include <string> #include <sstream> using namespace std; // use the namespaces using namespace GenericUtils; IPv4::IPv4() {} // default constructor/destructor IPv4::~IPv4() {} string IPv4::IPint_to_IPquad(unsigned long ip) { // member implementation ostringstream ipstr; // use a stringstream ipstr << ((ip &0xff000000) >> 24) // Bitwise right shift << "." << ((ip &0x00ff0000) >> 16) << "." << ((ip &0x0000ff00) >> 8) << "." << ((ip &0x000000ff)); return ipstr.str(); }
#include "IPv4.h" #include <iostream> #include <string> using namespace std; int main (int argc, char* argv[]) { string ipstr; // define variables unsigned long ipint = 1347861486; // The IP in integer form GenericUtils::IPv4 iputils; // create an object of the class ipstr = iputils.IPint_to_IPquad(ipint); // call the class member cout << ipint << " = " << ipstr << endl; // print the result return 0; }Compile and execute with:
# g++ -c IPv4.cpp simplecpp.cpp # Compile in objects # g++ IPv4.o simplecpp.o -o simplecpp.exe # Link the objects to final executable # ./simplecpp.exe 1347861486 = 80.86.187.238Use
ldd to check which libraries are used by the executable and where they are located. Also used to check if a shared library is missing or if the executable is static.
# ldd /sbin/ifconfig # list dynamic object dependencies # ar rcs staticlib.a *.o # create static archive # ar t staticlib.a # print the objects list from the archive # ar x /usr/lib/libc.a version.o # extract an object file from the archive # nm version.o # show function members provided by object
CC = g++ CFLAGS = -O OBJS = IPv4.o simplecpp.o simplecpp: ${OBJS} ${CC} -o simplecpp ${CFLAGS} ${OBJS} clean: rm -f ${TARGET} ${OBJS}
| Linux Documentation | en.tldp.org |
| Linux Man Pages | www.linuxmanpages.com |
| Linux commands directory | www.oreillynet.com/linux/cmd |
| Linux doc man howtos | linux.die.net |
| FreeBSD Handbook | www.freebsd.org/handbook |
| FreeBSD Man Pages | www.freebsd.org/cgi/man.cgi |
| FreeBSD user wiki | www.freebsdwiki.net |
| Solaris Man Pages | docs.sun.com/app/docs/coll/40.10 |
| Rosetta Stone for Unix | bhami.com/rosetta.html (a Unix command translator) |
| Unix guide cross reference | unixguide.net/unixguide.shtml |
| Linux commands line list | www.linuxcmd.org |
| Short Linux reference | www.pixelbeat.org/cmdline.html |
| Little command line goodies | www.shell-fu.org |
That's all folks!