Commands tagged bash (821)

  • type partial command, kill this command, check something you forgot, yank the command, resume typing.

    Example : vim /etc/fstab ## damn <ctrl+u> sudo <ctrl+y> ## like a boss. Example 2 : sudo vim /root/bin/ ##uh... autocomplete doesn't work... <ctrl+u> sudo ls /root/bin ##ah! that's the name of the file! <ctrl+y> sudo vim /root/bin/ ##resume here! Thanks readline!


    223
    <ctrl+u> [...] <ctrl+y>
    adeverteuil · 2010-07-23 03:33:46 34
  • Close shell keeping all subprocess running


    147
    disown -a && exit
    prayer · 2009-04-10 12:22:34 33
  • Easy and fast access to often executed commands that are very long and complex.

    When using reverse-i-search you have to type some part of the command that you want to retrieve. However, if the command is very complex it might be difficult to recall the parts that will uniquely identify this command. Using the above trick it's possible to label your commands and access them easily by pressing ^R and typing the label (should be short and descriptive). UPDATE: One might suggest using aliases. But in that case it would be difficult to change some parts of the command (such as options, file/directory names, etc).


    100
    some_very_long_and_complex_command # label
    jamolkhon · 2009-09-08 05:58:27 30
  • Show apps that use internet connection at the moment. (Multi-Language)


    99
    lsof -P -i -n
    OJM · 2009-09-19 18:28:48 33
  • Set CDPATH to ease navigation

    CDPATH tells the cd command to look in this colon-separated list of directories for your destination. My preferred order are 1) the current directory, specified by the empty string between the = and the first colon, 2) the parent directory (so that I can cd lib instead of cd ../lib), 3) my home directory, and 4) my ~/projects directory.


    88
    CDPATH=:..:~:~/projects
    haivu · 2009-03-20 14:50:25 23
  • Insert the last command without the last argument (bash)

    /usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.google.com/ then !:- http://www.commandlinefu.com/ is the same as /usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.commandlinefu.com/


    78
    !:-
    new_user · 2010-05-15 15:12:47 18
  • mkdir & cd into it as single command

    The biggest advantage of this over the functions is that it is portable.


    60
    mkdir /home/foo/doc/bar && cd $_
    kzh · 2011-08-12 11:29:19 15
  • Stream YouTube URL directly to mplayer.

    This is the result of a several week venture without X. I found myself totally happy without X (and by extension without flash) and was able to do just about anything but watch YouTube videos... so this a the solution I came up with for that. I am sure this can be done better but this does indeed work... and tends to work far better than YouTube's ghetto proprietary flash player ;-) Replace $i with any YouTube ID you want and this will scrape the site for the _real_ URL to the full quality .FLV file on Youtube's server and will then will hand that over to mplayer (or vlc or whatever you want) to be streamed. In some browsers you can replace $i with just a % or put this in a shell script so all YouTube IDs can be handed directly off to your media player of choice for true streaming without the need for Flash or a downloader like clive. (I do however fully recommend clive if you wish to archive videos instead of streaming them) If any interest is shown I would be more than happy to provide similar commands for other sites. Most streaming flash players use similar logic to YouTube. Edit: 05/03/2011 - Updated line to work with current YouTube. It could be a lot prettier but I will probably follow up with another update when I figure out how to get rid of that pesky Grep. Sed should take that syntax... but it doesn't. Original (no longer working) command: mplayer -fs $(echo "http://youtube.com/get_video.php?$(curl -s $youtube_url | sed -n "/watch_fullscreen/s;.*\(video_id.\+\)&title.*;\1;p")") Show Sample Output


    58
    i="8uyxVmdaJ-w";mplayer -fs $(curl -s "http://www.youtube.com/get_video_info?&video_id=$i" | echo -e $(sed 's/%/\\x/g;s/.*\(v[0-9]\.lscache.*\)/http:\/\/\1/g') | grep -oP '^[^|,]*')
    lrvick · 2009-03-09 03:57:44 53
  • Define a quick calculator function

    defines a handy function for quick calculations from cli. once defined: ? 10*2+3 Show Sample Output


    58
    ? () { echo "$*" | bc -l; }
    fizz · 2009-06-28 20:15:30 27
  • Multiple variable assignments from command output in BASH

    This version uses read instead of eval.


    57
    read day month year <<< $(date +'%d %m %y')
    putnamhill · 2011-07-29 15:05:19 23
  • Job Control

    You're running a script, command, whatever.. You don't expect it to take long, now 5pm has rolled around and you're ready to go home... Wait, it's still running... You forgot to nohup it before running it... Suspend it, send it to the background, then disown it... The ouput wont go anywhere, but at least the command will still run... Show Sample Output


    53
    ^Z $bg $disown
    fall0ut · 2009-03-17 21:52:52 27
  • Show apps that use internet connection at the moment. (Multi-Language)

    for one line per process: ss -p | cat for established sockets only: ss -p | grep STA for just process names: ss -p | cut -f2 -sd\" or ss -p | grep STA | cut -f2 -d\"


    52
    ss -p
    Escher · 2009-09-19 21:55:01 14
  • Search for a <pattern> string inside all files in the current directory

    This is how I typically grep. -R recurse into subdirectories, -n show line numbers of matches, -i ignore case, -s suppress "doesn't exist" and "can't read" messages, -I ignore binary files (technically, process them as having no matches, important for showing inverted results with -v) I have grep aliased to "grep --color=auto" as well, but that's a matter of formatting not function.


    49
    grep -RnisI <pattern> *
    birnam · 2009-09-22 15:09:43 31
  • Show numerical values for each of the 256 colors in bash

    Same as http://www.commandlinefu.com/commands/view/5876, but for bash. This will show a numerical value for each of the 256 colors in bash. Everything in the command is a bash builtin, so it should run on any platform where bash is installed. Prints one color per line. If someone is interested in formatting the output, paste the alternative.


    49
    for code in {0..255}; do echo -e "\e[38;05;${code}m $code: Test"; done
    scribe · 2010-06-19 02:14:42 14
  • List all bash shortcuts

    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 16
  • Compare two directory trees.

    This uses Bash's "process substitution" feature to compare (using diff) the output of two different process pipelines.


    35
    diff <(cd dir1 && find | sort) <(cd dir2 && find | sort)
    mbirk · 2009-05-21 04:44:29 45
  • Show apps that use internet connection at the moment.

    show only the name of the apps that are using internet Show Sample Output


    35
    lsof -P -i -n | cut -f 1 -d " "| uniq | tail -n +2
    edo · 2009-09-19 21:23:54 25
  • Create a directory and change into it at the same time

    How often do you make a directory (or series of directories) and then change into it to do whatever? 99% of the time that is what I do. This BASH function 'md' will make the directory path then immediately change to the new directory. By using the 'mkdir -p' switch, the intermediate directories are created as well if they do not exist. Show Sample Output


    32
    md () { mkdir -p "$@" && cd "$@"; }
    drewk · 2009-09-24 16:09:19 20
  • delete a line from your shell history

    If you're a moron like me, sometimes your fingers get away from you and you, for example, enter your password when you're already authenticated to ssh-agent, sudo, etc., and your password ends up in shell history. Here's how to get it out. Show Sample Output


    31
    history -d
    sud0er · 2009-04-27 20:19:09 19
  • easily find megabyte eating files or directories

    sorts the files by integer megabytes, which should be enough to (interactively) find the space wasters. Now you can dush for the above output, dush -n 3 for only the 3 biggest files and so on. It's always a good idea to have this line in your .profile or .bashrc Show Sample Output


    29
    alias dush="du -sm *|sort -n|tail"
    funky · 2010-03-26 10:18:57 15
  • Alias HEAD for automatic smart output

    Run the alias command, then issue ps aux | head and resize your terminal window (putty/console/hyperterm/xterm/etc) then issue the same command and you'll understand. ${LINES:-`tput lines 2>/dev/null||echo -n 12`} Insructs the shell that if LINES is not set or null to use the output from `tput lines` ( ncurses based terminal access ) to get the number of lines in your terminal. But furthermore, in case that doesn't work either, it will default to using the deafault of 12 (-2 = 10). The default for HEAD is to output the first 10 lines, this alias changes the default to output the first x lines instead, where x is the number of lines currently displayed on your terminal - 2. The -2 is there so that the top line displayed is the command you ran that used HEAD, ie the prompt. Depending on whether your PS1 and/or PROMPT_COMMAND output more than 1 line (mine is 3) you will want to increase from -2. So with my prompt being the following, I need -7, or - 5 if I only want to display the commandline at the top. ( https://www.askapache.com/linux/bash-power-prompt/ ) 275MB/748MB [7995:7993 - 0:186] 06:26:49 Thu Apr 08 [askapache@n1-backbone5:/dev/pts/0 +1] ~ In most shells the LINES variable is created automatically at login and updated when the terminal is resized (28 linux, 23/20 others for SIGWINCH) to contain the number of vertical lines that can fit in your terminal window. Because the alias doesn't hard-code the current LINES but relys on the $LINES variable, this is a dynamic alias that will always work on a tty device. Show Sample Output


    27
    alias head='head -n $((${LINES:-`tput lines 2>/dev/null||echo -n 12`} - 2))'
    AskApache · 2010-04-08 22:37:06 14
  • Pipe stdout and stderr, etc., to separate commands

    You can use [n]> combined with >(cmd) to attach the various output file descriptors to be the input of different commands.


    26
    some_command > >(/bin/cmd_for_stdout) 2> >(/bin/cmd_for_stderr)
    tylerl · 2009-12-01 03:58:04 6
  • Go to parent directory of filename edited in last command

    Uses the last argument of the last executed command, and gets the directory name from it. Use $!:t for the filename alone, without the dirname. Show Sample Output


    25
    cd !$:h
    lingo · 2009-08-07 00:37:08 10
  • April Fools' Day Prank

    Add this to a fiend's .bashrc. PROMPT_COMMAND will run just before a prompt is drawn. RANDOM will be between 0 and 32768; in this case, it'll run about 1/10th of the time. \033 is the escape character. I'll call it \e for short. \e7 -- save cursor position. \e[%d;%dH -- move cursor to absolute position \e[4%dm \e[m -- draw a random color at that point \e8 -- restore position.


    25
    PROMPT_COMMAND='if [ $RANDOM -le 3200 ]; then printf "\0337\033[%d;%dH\033[4%dm \033[m\0338" $((RANDOM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); fi'
    hotdog003 · 2010-04-01 06:52:32 16
  • find geographical location of an ip address

    I save this to bin/iptrace and run "iptrace ipaddress" to get the Country, City and State of an ip address using the http://ipadress.com service. I add the following to my script to get a tinyurl of the map as well: URL=`lynx -dump http://www.ip-adress.com/ip_tracer/?QRY=$1|grep details|awk '{print $2}'` lynx -dump http://tinyurl.com/create.php?url=$URL|grep tinyurl|grep "19. http"|awk '{print $2}'


    24
    lynx -dump http://www.ip-adress.com/ip_tracer/?QRY=$1|grep address|egrep 'city|state|country'|awk '{print $3,$4,$5,$6,$7,$8}'|sed 's\ip address flag \\'|sed 's\My\\'
    leftyfb · 2009-02-25 17:16:56 27
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Search recursively to find a word or phrase in certain file types, such as C code
I have a bash alias for this command line and find it useful for searching C code for error messages. The -H tells grep to print the filename. you can omit the -i to match the case exactly or keep the -i for case-insensitive matching. This find command find all .c and .h files

List your installed Chromium extensions (with url to each page)
Gives you a list for all installed chrome (chromium) extensions with URL to the page of the extension. With this you can easy add a new Bookmark folder called "extensions" add every URL to that folder, so it will be synced and you can access the names from every computer you are logged in. ------------------------------------------------------------------------------------------------------------------ Only tested with chromium, for chrome you maybe have to change the find $PATH.

Convert Squid unixtime logs in human-readable ones
On-the-fly conversion of Unix Time to human-readable in Squid's access.log

Recursively remove all empty directories

Run a command multiple times with different subcommands
it's nice to be able to use the command `ls program.{h,c,cpp}`. This expands to `ls program.h program.c program.cpp`. Note: This is a text expansion, not a shell wildcard type expansion that looks at matching file names to calculate the expansion. More details at http://www.linuxjournal.com/content/bash-brace-expansion I often run multiple commands (like apt-get) one after the other with different subcommands. Just for fun this wraps the whole thing into a single line that uses brace expansion.

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

sed /pat/!d without using sed (no RE; limited to shell patterns aka globbing)
POSIX requires this "string truncating" functionality. might as well use it, at least for very small tasks where invoking sed and using RE is overkill.

Silently ensures that a FS is mounted on the given mount point (checks if it's OK, otherwise unmount, create dir and mount)
In my example, the mount point is /media/mpdr1 and the FS is /dev/sdd1 /mountpoint-path = /media/mpdr1 filesystem=/dev/sdd1 Why this command ? Well, in fact, with some external devices I used to face some issues : during data transfer from the device to the internal drive, some errors occurred and the device was unmounted and remounted again in a different folder. In such situations, the command mountpoint gave a positive result even if the FS wasn't properly mounted, that's why I added the df part. And if the device is not properly mounted, the command tries to unmount, to create the folder (if it exists already it will also work) and finally mount the FS on the given mount point.

List all databases in Postgres and their (byte/human) sizes, ordering by byte size descending
Get a listing of all of your databases in Postgres and their sizes, ordering by the largest size first. Requires that you give the -d parameter a valid database name that you can connect to.

print a python-script (or any other code) with syntax-highlighting and no loss of indentation

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