All commands (14,211)

  • The title is optional. Options: -t: expire time in milliseconds. -u: urgency (low, normal, critical). -i: icon path. On Debian-based systems you may need to install the 'libnotify-bin' package. Useful to advise when a wget download or a simulation ends. Example: wget URL ; notify-send "Done"


    47
    notify-send ["<title>"] "<body>"
    o6291408 · 2009-04-29 10:05:20 24
  • "-o loop" lets you use a file as a block device


    47
    mount /path/to/file.iso /mnt/cdrom -oloop
    nerd65536 · 2009-02-05 17:28:06 35

  • 46
    timeout 5s COMMAND
    kev · 2011-11-19 06:14:33 13
  • In this case it's better do to use the dedicated tool


    45
    ssh-keygen -R <the_offending_host>
    bunam · 2010-07-11 19:37:24 17
  • If you want a visual representation of the parent/child relationships between processes, this is one easy way to do it. It's useful in debugging collections of shell scripts, because it provides something like a call traceback. When a shell script breaks, just remember "awwfux".


    45
    ps awwfux | less -S
    ToyKeeper · 2009-07-04 09:39:28 15
  • 'dpkg -S' just matches the string you supply it, so just using 'ls' as an argument matches any file from any package that has 'ls' anywhere in the filename. So usually it's a good idea to use an absolute path. You can see in the second example that 12 thousand files that are known to dpkg match the bare string 'ls'. Show Sample Output


    45
    dpkg -S /usr/bin/ls
    bwoodacre · 2009-04-18 18:18:23 25
  • Good for one off jobs that you want to run at a quiet time. The default threshold is a load average of 0.8 but this can be set using atrun. Show Sample Output


    45
    echo "rm -rf /unwanted-but-large/folder" | batch
    root · 2009-02-04 19:07:52 112
  • You can get one specific line during any procedure. Very interesting to be used when you know what line you want. Show Sample Output


    44
    sed -n 5p <file>
    Waldirio · 2009-10-15 11:00:48 142
  • Directly attach a remote screen session (saves a useless parent bash process)


    44
    ssh -t remote_host screen -r
    recursiverse · 2009-07-23 06:15:04 84
  • This command shows the various shortcuts that can be use in bash, including Ctrl+L, Ctrl+R, etc... You can translate "\C-y" to Ctrl+y, for example. Show Sample Output


    43
    bind -P
    ricardofunke · 2012-05-28 18:51:59 19
  • RTFMFTW.


    42
    rtfm() { help $@ || man $@ || $BROWSER "http://www.google.com/search?q=$@"; }
    hunterm · 2011-01-05 02:53:38 328
  • This command takes a snapshot of the open files for a PID 1234 then waits 10 seconds and takes another snapshot of the same PID, it then displays the difference between each snapshot to give you an insight into what the application is doing.


    42
    diff <(lsof -p 1234) <(sleep 10; lsof -p 1234)
    zlemini · 2010-03-15 22:55:32 14

  • 42
    tar -tf <file.tar.gz> | xargs rm -r
    prayer · 2009-07-06 22:23:11 22
  • Sometimes you need to use a port that is already opened by some program , and you don't know who to "kill" for it to release - so, now you do ! Show Sample Output


    42
    lsof -i tcp:80
    ar_levi · 2009-04-16 14:51:53 288

  • 41
    until !!; do :; done
    unixmonkey21806 · 2013-05-14 18:08:54 70
  • run 'nc yourip 5000', 'nc yourip 5001' or 'nc yourip 5002' elsewhere will produce an exact same mirror of your shell. This is handy when you want to show someone else some amazing stuff in your shell without giving them control over it.


    41
    script -qf | tee >(nc -kl 5000) >(nc -kl 5001) >(nc -kl 5002)
    clvv · 2010-10-11 07:55:30 25
  • Short command, easy to remember


    41
    curl ifconfig.me
    CodSpirit · 2010-08-01 13:56:01 14
  • In Python version 3, the module was merged into http.server. Gentlemen, change your aliases. Show Sample Output


    40
    python -m http.server
    Alanceil · 2010-12-17 12:52:45 47
  • Of course you need to be able to access host A for this ;-)


    40
    ssh -t hostA ssh hostB
    0x89 · 2009-08-27 21:35:19 34
  • Shorter, easier to remember version of cmd#7636 NTP is better, but there are situations where it can't be used. In those cases, you can do this to sync the local time to a server. Show Sample Output


    39
    date --set="$(ssh user@server date)"
    splante · 2011-08-30 20:03:06 69
  • -d: list directory entries instead of contents, and do not dereference symbolic links


    39
    ls -d */
    brianmuckian · 2009-10-08 22:07:22 32
  • Google just released a new commend line tool offering all sorts of new services from the commend line. One of them is uploading a youtube video but there are plenty more google services to interact with. Download it here: http://code.google.com/p/googlecl/ Manual: http://code.google.com/p/googlecl/wiki/Manual This specific command courtesy of lifehacker:http://lifehacker.com/5568817/ Though all can be found in manual page linked above. Show Sample Output


    38
    google docs edit --title "To-Do List" --editor vim
    spiffwalker · 2010-06-21 16:15:42 19
  • The empty file /forcefsck causes the file system check fsck to be run next time you boot up, after which it will be removed. This works too: sudo >/forcefsck


    38
    sudo touch /forcefsck
    johnraff · 2009-10-29 17:04:47 19
  • If you enable multiuser, then you can permit others to share your screen session. The following conditions apply: 1. screen must be suid root; 2. "multiuser on" must be configured in ~/.screenrc; 3. control the others user(s) access with "aclchg": # ----- from ~/.screenrc-users ----- aclchg someuser +rx "#?" #enable r/o access to "someuser" aclchg someuser -x "#,at,aclchg,acladd,acldel,quit" # don't allow these aclchg otheruser +rwx "#?" # enable r/w access to "otheruser" aclchg otheruser -x "#,at,aclchg,acladd,acldel,quit" # don't allow them to use these commands # ----- After doing this (once), you start your session with: $ screen Then, the other user can join your terminal session(s) with youruserid: $ screen -r youruserid/ Note: the trailing "/" is required. Multiple users can share the same screen simultaneously, each with independent access controlled precisely with "aclchg" in the ~/.screenrc file. I use the following setup: # ~/.screenrc-base # default screenrc on any host source $HOME/.screenrc-base source $HOME/.screenrc-$HOST source $HOME/.screenrc-users # ----- Then, the base configurations are in ~/.screenrc-base; the host-specific configurations are in ~/.screenrc-$HOST, and the user configurations are in ~/.screenrc-users. The host-specific .screenrc file might contain some host-specific screen commands; e.g.: # ~/.screen-myhost # ----- screen -t 'anywhere' /bin/tcsh screen -t 'anywhere1' /bin/tcsh # ---- The .screenrc-base contains: # ~/.screenrc-base ## I find typing ^a (Control-a) awkward. So I set the escape key to CTRL-j instead of a. escape ^Jj termcapinfo xterm* ti@:te@: autodetach on zombie kr verbose on multiuser on


    38
    % screen -r someuser/
    totoro · 2009-03-25 23:59:38 13
  • EDIT: command updated to support accented characters! Works in any of 58 google supported languages (some sound like crap, english is the best IMO). You get a mp3 file containing your query in spoken language. There is a limit of 100 characters for the "q" parameter, so be careful. The "tl" parameter contains target language.


    37
    wget -q -U Mozilla -O output.mp3 "http://translate.google.com/translate_tts?ie=UTF-8&tl=en&q=hello+world
    sairon · 2011-03-08 14:05:36 24
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Schedule Nice Background Commands That Won't Die on Logout - Alternative to nohup and at
Check out the usage of 'trap', you may not have seen this one much. This command provides a way to schedule commands at certain times by running them after sleep finishes sleeping. In the example 'sleep 2h' sleeps for 2 hours. What is cool about this command is that it uses the 'trap' builtin bash command to remove the SIGHUP trap that normally exits all processes started by the shell upon logout. The 'trap 1' command then restores the normal SIGHUP behaviour. It also uses the 'nice -n 19' command which causes the sleep process to be run with minimal CPU. Further, it runs all the commands within the 2nd parentheses in the background. This is sweet cuz you can fire off as many of these as you want. Very helpful for shell scripts.

video volume boost

Insert a line at the top of a text file without sed or awk or bash loops
Yet another way to add a line at the top a of text file with the help of the tac command (reverse cat).

list block devices
Shows all block devices in a tree with descruptions of what they are.

Produce a pseudo random password with given length in base 64
Of course you will have to install Digest::SHA and perl before this will work :) Maximum length is 43 for SHA256. If you need more, use SHA512 or the hexadecimal form: sha256_hex()

Merge video files together using mencoder (part of mplayer)
Using mplayer's mencoder, you can merge video files together. '-oac' specifies the audio encoding (here copy, to just copy and not compress) '-ovc' specifies the video encoding (same thing).

Clean swap area after using a memory hogging application
When you run a memory intensive application (VirtualBox, large java application, etc) swap area is used as soon as memory becomes insufficient. After you close the program, the data in swap is not put back on memory and that decreases the responsiveness. Swapoff disables the swap area and forces system to put swap data be placed in memory. Since running without a swap area might be detrimental, swapon should be used to activate swap again. Both swapoff and swapon require root privileges.

Block all IPv4 addresses that has brute forcing our ssh server
For ipv6 use: grep -oE "\b([0-9A-Fa-f]{1,4}:){7}[0-9A-Fa-f]{1,4}\b"

MySQL dump restore with progress bar and ETA
Display a progress bar while restoring a MySQL dump.

To find the uptime of each process-id of particular service or process


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