Commands tagged Linux (266)

  • will purge: only installed apps: /^ii/!d avoiding current kernel stuff: /'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d using app names: s/^[^ ]* [^ ]* \([^ ]*\).*/\1/ avoiding stuff without a version number: /[0-9]/!d


    7
    dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' | xargs sudo apt-get -y purge
    plasticdoc · 2009-06-19 10:11:00 9
  • Remove newlines from output. One character shorter than awk /./ filename and doesn't use a superfluous cat. To be fair though, I'm pretty sure fraktil was thinking being able to nuke newlines from any command is much more useful than just from one file.


    7
    grep . filename
    TheMightyBuzzard · 2009-08-09 05:33:58 12
  • If you use Linux in a Windows domain and there are N days to expiry, this is how you can change it without resorting to a windows machine.


    7
    smbpasswd -r <domain-server> -U <user name>
    greppo · 2009-08-12 07:46:48 11
  • Will edit *.db files in the same directory with todays date. Useful for doing a mass update to domains on a nameserver, adding spf records, etc. Looks for a string starting with 200 or 201 followed by 7 numbers, and replaces with todays date. This won't overwrite Ip's but i would still do some double checking after running this. Make sure your server's date is correct, otherwise insert your own serial number. rndc reload should usually follow this command.


    7
    sed -i 's/20[0-1][0-9]\{7\}/'`date +%Y%m%d%I`'/g' *.db
    alf · 2010-03-24 07:28:58 10
  • Note the double space: "...^ii␣␣linux-image-2..." Like 5813, but fixes two bugs: [1]This leaves the meta-packages 'linux-headers-generic' and 'linux-image-generic' alone so that automatic upgrades work correctly in the future. [2]Kernels newer than the currently running one are left alone (this can happen if you didn't reboot after installing a new kernel). I'm bummed that this took 228 characters. I'd like to see a simpler version. Show Sample Output


    7
    aptitude remove $(dpkg -l|awk '/^ii linux-image-2/{print $2}'|sed 's/linux-image-//'|awk -v v=`uname -r` 'v>$0'|sed 's/-generic//'|awk '{printf("linux-headers-%s\nlinux-headers-%s-generic\nlinux-image-%s-generic\n",$0,$0,$0)}')
    __ · 2010-12-11 11:38:15 7
  • If you cat the file, all the parts of the command line are bunched up. If you use tr to convert the nulls to spaces, you're still left without a newline unless you add another step. This command does everything for you. Show Sample Output


    7
    xargs -0a /proc/27288/cmdline echo
    dennisw · 2015-09-25 17:35:11 17
  • The output format is given by the -printf parameter: %T@ = modify time in seconds since Jan. 1, 1970, 00:00 GMT, with fractional part. Mandatory, hidden in the end. %TY-%Tm-%Td %TH:%TM:%.2TS = modify time as YYYY-MM-DD HH:MM:SS. Optional. %p = file path Refer to http://linux.die.net/man/1/find for more about -printf formatting. ------------------------ sort -nr = sort numerically and reverse (higher values - most recent timestamp - first) head -n 5 = get only 5 first lines (change 5 to whatever you want) cut -f2- -d" " = trim first field (timestamp, used only for sorting) ------------------------ Very useful for building scripts for detecting malicious files upload and malware injections. Show Sample Output


    7
    find . -type f -printf '%T@ %TY-%Tm-%Td %TH:%TM:%.2TS %p\n' | sort -nr | head -n 5 | cut -f2- -d" "
    paulera · 2016-03-23 11:56:39 11
  • Using the grep command, retrieve all lines from any log files in /var/log/ that have one of the problem states


    6
    grep -2 -iIr "err\|warn\|fail\|crit" /var/log/*
    miketheman · 2009-06-17 19:41:04 10

  • 6
    strings /dev/mem|less
    fraktil · 2009-08-09 00:56:06 8
  • Listens for events in the directory. Each created file is displayed on stdout. Then each fileline is read by the loop and a command is run. This can be used to force permissions in a directory, as an alternative for umask. More details: http://en.positon.org/post/A-solution-to-the-umask-problem%3A-inotify-to-force-permissions


    6
    inotifywait -mrq -e CREATE --format %w%f /path/to/dir | while read FILE; do chmod g=u "$FILE"; done
    dooblem · 2010-10-21 23:36:02 4
  • Shows all configurations to apt and dpkg, rarely changed, you probably still have the default configuration. Go ahead and explore your configuration if you dare, perhaps change your apt-cache directory, Dir::Cache "var/cache/apt/"; or the names of the log files. Show Sample Output


    6
    apt-config dump
    LinuxMan · 2011-12-13 19:11:02 7
  • With this command you can get a previous or future date or time. Where can you use this? How about finding all files modified or created in the last 5 mins? touch -t `echo $(date -d "5 minute ago" "+%G%m%d%H%M.%S")` me && find . -type f -newer me List all directories created since last week? touch -t `echo $(date -d "1 week ago" "+%G%m%d%H%M.%S")` me && find . -type d -cnewer me I'm sure you can think of more ways to use it. Requires coreutils package. Show Sample Output


    5
    date -d '1 day ago'; date -d '11 hour ago'; date -d '2 hour ago - 3 minute'; date -d '16 hour'
    LrdShaper · 2009-06-01 10:41:56 9
  • or you can add "-x" to get a typical hexdump like output Show Sample Output


    5
    socat -v tcp4-l:<port> tcp4:<host>:<port>
    sitaram · 2009-09-25 17:10:16 4
  • Just after you type enter, you have 3 seconds to switch window, then "texthere" will be "typed" in the X11 application that has focus. Very useful to beat your score at games such as "How fast can you type A-Z".


    5
    sleep 3 && xdotool type --delay 0ms texthere
    drinkcat · 2010-02-18 11:44:18 20
  • Cleans all files in /tmp that have been accessed at least 2 days ago.


    5
    find /tmp -type f -atime +1 -delete
    mattoufoutu · 2010-05-11 17:08:49 5

  • 5
    while inotifywait -r -e MODIFY dir/; do make; done;
    prayer · 2010-06-08 23:34:00 6
  • Tired copy paste to get opcode from objdump huh ? Get more @ http://gunslingerc0de.wordpress.com Show Sample Output


    5
    objdump -d ./PROGRAM|grep '[0-9a-f]:'|grep -v 'file'|cut -f2 -d:|cut -f1-6 -d' '|tr -s ' '|tr '\t' ' '|sed 's/ $//g'|sed 's/ /\\x/g'|paste -d '' -s |sed 's/^/"/'|sed 's/$/"/g'
    gunslinger_ · 2010-07-11 15:44:48 112
  • Takes all .flac directories, feeds them into a simple transcode pipeline to spit out .wavs with the same name (but correct extension).


    5
    for i in *.flac; do gst-launch filesrc location="$i" ! flacdec ! wavenc ! filesink location="${i%.flac}.wav"; done
    JamesHarrison · 2010-07-17 22:48:22 5
  • Use as: $ s host1 Will ssh to remote host upon first invocation. Then use C-a d to detatch. Running "s host1" again will resume the shell session on the remote host. Only useful in LAN environment. You'd want to start the screen on the remote host over a WAN. Adapted from Hack 34 in Linux Server Hacks 2nd Addition.


    5
    s() { screen -d -RR -m -S "$1" -t "$USER"@"$1" ssh "$1"; }
    salamando · 2012-09-07 23:02:52 5

  • 5
    rename 's/.xls/.ods/g' *.xls
    jedifu · 2013-09-12 13:42:56 8
  • The "proportional set size" is probably the closest representation of how much active memory a process is using in the Linux virtual memory stack. This number should also closely represent the %mem found in ps(1), htop(1), and other utilities. Show Sample Output


    5
    echo 0$(awk '/Pss/ {printf "+"$2}' /proc/$PID/smaps)|bc
    atoponce · 2013-09-26 18:20:22 10
  • This is a commodity one-liner that uses ShellCheck to assure some quality on bash and sh scripts under a specific directory. It ignores the files in .git directory. Just substitute "./.git/*" with "./.svn/*" for older and booring centralized version control. Just substitute ShellCheck with "rm" if your scripts are crap and you want to get rid of them :)


    5
    find . -type f ! -path "./.git/*" -exec sh -c "head -n 1 {} | egrep -a 'bin/bash|bin/sh' >/dev/null" \; -print -exec shellcheck {} \;
    brx75x · 2017-03-16 08:43:56 24
  • the middle command between the ; and ; is the vi commands that insert that line into the last line of the file, the esc with the carets is literally hitting the escape key, you have to have the smbfs package installed to do it, I use it to access my iTunes music on my mac from my linux PC's with amarok so I can play the music anywhere in the house. among other things, it allows you to access the files on that share from your computer anytime you're on that network.


    4
    sudo vi /etc/fstab; Go//smb-share/gino /mnt/place smbfs defaults,username=gino,password=pass 0 0<esc>:wq; mount //smb-share/gino
    GinoMan2440 · 2009-04-02 16:04:35 9
  • will show: installed linux headers, image, or modules: /^ii/!d avoiding current kernel: /'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d only application names: s/^[^ ]* [^ ]* \([^ ]*\).*/\1/ avoiding stuff without a version number: /[0-9]/!d Show Sample Output


    4
    dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d'
    plasticdoc · 2009-06-19 10:23:38 8
  • Instead of calculating the offset and providing an offset option to mount, let lomount do the job for you by just providing the partition number you would like to loop mount.


    4
    lomount -diskimage /path/to/your/backup.img -partition 1 /mnt/foo
    olorin · 2009-07-22 11:32:52 16
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Get absolut path to your bash-script
Another way of doing it that's a bit clearer. I'm a fan of readable code.

Delete Last Line of a File if it is Blank
Use sed to remove the last line of a file only if it is empty.

Show current pathname in title of terminal
This helps to keep track of what is going on when you have several tabs open in your terminal. The title automatically changes when you change directories.

Sorted, recursive long file listing
Tells you everything you could ever want to know about all files and subdirectories. Great for package creators. Totally secure too. On my Slackware box, this gets set upon login: $ LS_OPTIONS='-F -b -T 0 --color=auto' and $ alias ls='/bin/ls $LS_OPTIONS' which works great.

ls -hog --> a more compact ls -l
I often deal with long file names and the 'ls -l' command leaves very little room for file names. An alternative is to use the -h -o and -g flags (or together, -hog). * The -h flag produces human-readable file size (e.g. 91K instead of 92728) * The -o suppresses the owner column * The -g suppresses the group column Since I use to alias ll='ls -l', I now do alias ll='ls -hog'

pretend to be busy in office to enjoy a cup of coffee
The first parameter after timeout is the key parameter; number of seconds to wait. With a 6 you have 600 seconds for your coffee break (10min).

Find recursively, from current directory down, files and directories whose names contain single or multiple whitespaces and replace each such occurrence with a single underscore.
Note the g for global in the perl expression; without it, only the first occurrence in the name would be replaced.

Show me a histogram of the busiest minutes in a log file:
Busiest seconds: $ cat /var/log/secure.log | awk '{print substr($0,0,15)}' | uniq -c | sort -nr | awk '{printf("\n%s ",$0) ; for (i = 0; i

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

Screencast with ffmpeg x11grab
requires ffmpeg & xwininfo to be installed replace hw:0,0 with pulse if you like using pulseaudio press q to quit


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