# Linux commandline tips # Bash tips ``` ^r Reverse search the command history ^a Return to the start of the command you're typing ^e Go to the end of the command you're typing ^u Cut everything before the cursor to a special clipboard ^k Cut everything after the cursor to a special clipboard ^y Paste from the special clipboard that Ctrl + u and Ctrl + k save their data to ^t Swap the two characters before the cursor (you can actually use this to transport a character from the left to the right, try it!) ^w Delete the word / argument left of the cursor ^l Clear the screen history lists command history !61 executes command on line 61 ls -l /etc/passwd stat !$ no need to repeat argument on second line man -k searches in all man pages for ls *.mp3 | xargs rm ls *.mp3 | xargs -i cp {} /home/bla ls *.mp3 -d -> stays in current dir and doesn't enter mp3/ ``` - start a restricted shell (no cd, etc) to test programs `# bash -r` - start shell with options `# bash -O [modification]` `autocd -> use the argument as cd command` `cd-spell -> corrects dir names` `dirspell -> corrects dir names in file completion` `no-caseglob -> case insensitive` --- to run commands: `# command1 && command2` logical AND :: run command1, if ok then run command2 `# command1 || command2` logical OR :: run command2 only if command1 fails # cp `cp -rv ` gives feedback `cp -p` preserves original date/time # dd use blocks of 64k and report every 10Mb: `dd if=/dev/hda | buffer -s 64k -S 10m > image` or, from other console: `kill -SIGUSR1 $(pidof dd)` # df `df -type=ext3,ReiserFS` `df -H human readable` # find find all files in your homedir modified or created today `find ~ -type f -mtime 0` case insentive search `find . -iname "*mp3"` find files and directories in yor homedir not created by you `find ~ ! -user ${USER}` and fix this `find ~ ! -user ${USER} -exec sudo chown ${USER}:"{}" \;` find duplicates PvdM `find . -type f -exec md5sum '{}' ';' | sort | uniq --all-repeated=separate -w 15` # free `free -m -> megabytes` `free -t -> totals` `free -s[seconds] -> update interval` watch the line with +/- buffers: **free** indicates memory that can be freed instantaniously **used** is all memory being used # grep `grep -A2 bla greps 2 lines after` `grep -B3 bla greps 3 lines before` # history `# history -d [postition] -> remove specific command` `# history -c -> clear entire history` # iotop monitors io proces `iotop -o makes output more readable by showing only processes causing io right now ` `iotop -d10 refresh interval` `iotop -o -b -d10 -n30 > io.txt batch mode: write io status 30 times to file at 10s interval` # iperf `iperf -s -w128k run server for performance benchmark` `iperf -c `` -w128k -t30 -r run client` `iperf -c `` -w128k -t30 -d run client in two directions, full duplex` # kill kill -l shows instructions ` 1  SIGHUP   restart immediately after terminating, or triggers reconfiguration of background service` ` 2  SIGINT   Ctrl+c from the keyboard, terminate!` ` 3  SIGQUIT  Ctrl+\ from the keyboard, terminate with coredump` ` 9  SIGKILL  force terminate, extreme signal that can't ignored` `11  SIGSEGV  program attempted an invalid memory reference, terminate with coredump` `15  SIGTERM  request to terminate and cleanup` `19  SIGSTOP  interrupts the process until you enter SIGCONT to continue` `kill -19 9102 10234  stops several processes` `killall -19 ssh      sends all ssh connections to sleep` `killall -19 -i ssh   interactive mode (recommended)` # lsof `lsof list open files` `lsof -i :22 list all ssh connections (same :ssh)` `lsof -i@10.0.0.1 list all connections from 10.0.0.1` `lsof -i@amsterdam.nl list all connections from domain` `lsof -u username list all open files from username` `lsof -c bash list open files related to bash` `lsof -c /log/ list all open files from all processes containing log` # lspci `lspci -v ` `lspci -vv` `lspci -vvv` `lspci -nn -> show names & numerical ` `lspci -k -> show kernel modules associated with the device` # more or less `+`` number of line from which to start displaying` `z ``  number of lines to jump forward` `y `` number of lines to jump back` `-I ignore case when searching` `-V underline tabs, line endings` `/`` highlights all ocurrences of search` # pgrep `pgrep ssh lists all ssh processes` `pgrep -l ssh shows names` `pgrep -f  shows full commandline` `pgrep -u show user` # ping `ping 0 -> pings localhost` `ping c 5 nu.nl -> pings 5 times` `ping -f host -> floods the host` `ping -a IP -> gives audible beep Note: It can give beep only from terminal number 1 through 7 and gnome-terminal ( It will not work in console ).` `ping -q ip -> show only summary` `ping -s 100 -> change packet size` `Pressing CTRL+| (Control key followed by pipe symbol) for the shows the summary in between, and continues with it packet sending and receiving process.` `ping hop1 hop2 hop3 .. hopN destination` `ping -R 192.168.1.63 -> Record and print route of how ECHO_REQUEST sent and ECHO_REPLY received` # pkill understands the same options as pgrep `pkill -19 ssh` `pkill -19 -u joop stop joop's processes` # ps show how long a process is running `ps -o pid,etime,cmd `pidof amarok`` show memory usage per process `ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS` # pstree `pstree -a shows processes tree structure with program's parameters` `pstree -h highlights own process ` `pstree -H `` highlights process id` `pstree -u shows user` # stat shows status of file `stat /etc/passwd   ` `stat -c "%x %n" /etc/passwd      formatted to show time` # swapon `swapon -s see size and usage` # tail or head `--retry keep monitoring the file ` `-s seconds how often monitoring retry` `-pid `` stops tail from running if PID stops running` # tar `tar zxf `` -> extracts file` # top ``` PID programma id USER gebruiker PR prioriteit van de taak NI nice value VIRT virtuele geheugen gebruik RES fysieke geheugen gebruik SHR deel v/h gebeugen dat mogelijk met andere taken wordt gedeeld %CPU percentage processorgebruik %MEM percentage geheugengebruik TIME+ de tijd dat de taak op de cpu heeft gedraaid COMMAND de naam van de taak ``` keys: z: enable color mode. x: show sorted column in different color < >: change sorted column u \[user\]: show only users processes d: delay in sec show only user user `#top -u user` # zombies `ps aux | grep defunct` # AutoYast create autoyast file through icon in Yast2->autoyast `www.suse.de/~ug (Uwe Gansert)` # Midnight Commander (MC) The standard colorpallette is incredibly hard to read in certain terminals, like yakuake. For readable colors (mostly black and green), enter in your ~/.mc/ini file the following line: `[Colors]` `base_color=lightgray,green:normal=green,default:selected=white,gray:marked=yellow,default:markselect=yellow,gray:directory=blue,default:executable=brightgreen,default:link=cyan,default:device=brightmagenta,default:special=lightgray,default:errors=red,default:reverse=green,default:gauge=green,default:input=white,gray:dnormal=green,gray:dfocus=brightgreen,gray:dhotnormal=cyan,gray:dhotfocus=brightcyan,gray:menu=green,default:menuhot=cyan,default:menusel=green,gray:menuhotsel=cyan,default:helpnormal=cyan,default:editnormal=green,default:editbold=blue,default:editmarked=gray,blue:stalelink=red,default` # tune kernelparameters stored in /proc/sys/ gone after reboot sysctl is a service that reads sysctl.conf during boot and read parameters from there -> makes it permanent `# ulimit -a` givesinfo about system resources limitations