Commands tagged bash (821)

  • Define an alias with a correct completion

    In Bash, when defining an alias, one usually loses the completion related to the function used in that alias (that completion is usually defined in /etc/bash_completion using the complete builtin). It's easy to reuse the work done for that completion in order to have smart completion for our alias. That's what is done by this command line (that's only an example but it may be very easy to reuse). Note 1 : You can use given command line in a loop "for old in apt-get apt-cache" if you want to define aliases like that for many commands. Note 2 : You can put the output of the command directly in your .bashrc file (after the ". /etc/bash_completion") to always have the alias and its completion Show Sample Output


    4
    old='apt-get'; new="su-${old}"; command="sudo ${old}"; alias "${new}=${command}"; $( complete | sed -n "s/${old}$/${new}/p" ); alias ${new}; complete -p ${new}
    Josay · 2009-08-10 00:15:05 4
  • Create Encrypted WordPress MySQL Backup without any DB details, just the wp-config.php

    The coolest way I've found to backup a wordpress mysql database using encryption, and using local variables created directly from the wp-config.php file so that you don't have to type them- which would allow someone sniffing your terminal or viewing your shell history to see your info. I use a variation of this for my servers that have hundreds of wordpress installs and databases by using a find command for the wp-config.php file and passing that through xargs to my function. Show Sample Output


    4
    eval $(sed -n "s/^d[^D]*DB_\([NUPH]\)[ASO].*',[^']*'\([^']*\)'.*/_\1='\2'/p" wp-config.php) && mysqldump --opt --add-drop-table -u$_U -p$_P -h$_H $_N | gpg -er AskApache >`date +%m%d%y-%H%M.$_N.sqls`
    AskApache · 2009-08-18 07:03:08 7
  • no more line wrapping in your terminal

    works on all unices. Show Sample Output


    4
    function nowrap { export COLS=`tput cols` ; cut -c-$COLS ; unset COLS ; }
    mobidyc · 2009-09-11 15:07:00 13
  • Change Title of Terminal Window to Verbose Info useful at Login

    I usually have 5 or more ssh connections to various servers, and putting this command in my .bash_profile file makes my putty window or x terminal window title change to this easily recognizable and descriptive text. Includes the username, group, server hostname, where I am connecting from (for SSH tunneling), which device pts, current server load, and how many processes are running. You can also use this for your PROMPT_COMMAND variable, which updates the window title to the current values each time you exec a command. I prefix running this in my .bash_profile with [[ ! -z "$SSH_TTY" ]] && which makes sure it only does this when connecting via SSH with a TTY. Here's some rougher examples from http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html # If set, the value is executed as a command prior to issuing each primary prompt. #H=$((hostname || uname -n) 2>/dev/null | sed 1q);W=$(whoami) #export PROMPT_COMMAND='echo -ne "\033]0;${W}@${H}:${PWD/#$HOME/~} ${SSH_TTY/\/dev\//} [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"`]\007"' #PROMPT_COMMAND='echo -ne "\033]0;`id -un`:`id -gn`@`hostname||uname -n 2>/dev/null|sed 1q` `command who -m|sed -e "s%^.* \(pts/[0-9]*\).*(\(.*\))%[\1] (\2)%g"` [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"` / `command ps aux|wc -l`]\007"' #[[ -z "$SSH_TTY" ]] || export PROMPT_COMMAND #[[ -z "$SSH_TTY" ]] && [[ -f /dev/stdout ]] && SSH_TTY=/dev/stdout And here's a simple function example for setting the title: function set_window_title(){ echo -e "\033]0; ${1:-$USER@$HOST - $SHLVL} \007"; } Show Sample Output


    4
    echo -ne "\033]0;`id -un`:`id -gn`@`hostname||uname -n|sed 1q` `who -m|sed -e "s%^.* \(pts/[0-9]*\).*(\(.*\))%[\1] (\2)%g"` [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"` / `ps aux|wc -l`]\007"
    AskApache · 2009-09-19 06:57:53 4
  • Show apps that use internet connection at the moment.

    This corrects duplicate output from the previous command. Show Sample Output


    4
    netstat -lantp | grep -i establ | awk -F/ '{print $2}' | sort | uniq
    HarimaKenji · 2009-09-19 14:42:31 7
  • Get ssh server fingerprints

    Get your server's fingerprints to give to users to verify when they ssh in. Publickey locations may vary by distro. Fingerprints should be provided out-of-band. Show Sample Output


    4
    ssh-keygen -l -f /etc/ssh/ssh_host_rsa_key.pub && ssh-keygen -l -f /etc/ssh/ssh_host_dsa_key.pub
    Mikelifeguard · 2009-10-26 17:52:41 4
  • Enable cd by variable names

    Usage: mydir=/very/long/path/to/a/dir cd mydir I often need to cd where no man wants to go (i.e. long path). by enabling the shell option cdable_vars, I can tell cd to assume the destination is the name of a variable.


    4
    shopt -s cdable_vars
    haivu · 2009-10-26 22:10:56 5
  • Output Detailed Process Tree for any User

    An easy function to get a process tree listing (very detailed) for all the processes of any gived user. This function is also in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html Show Sample Output


    4
    psu(){ command ps -Hcl -F S f -u ${1:-$USER}; }
    AskApache · 2009-11-13 06:10:33 4
  • Convert decimal numbers to binary

    Convert some decimal numbers to binary numbers. You could also build a general base-converter: function convBase { echo "ibase=$1; obase=$2; $3" | bc; } then you could write function decToBun { convBase 10 2 $1; } Show Sample Output


    4
    function decToBin { echo "ibase=10; obase=2; $1" | bc; }
    woxidu · 2009-11-24 22:57:58 3
  • Facebook Email Scraper

    (Apparently it is too long so I put it in sample output, I hope that is OK.) Run the long command (or put it in your .bashrc) in sample output then run: fbemailscraper YourFBEmail Password Voila! Your contacts' emails will appear. Facebook seems to have gotten rid of the picture encoding of emails and replaced it with a text based version making it easy to scrape! Needs curl to run and it was made pretty quickly so there might be bugs. Show Sample Output


    4
    fbemailscraper YourFBEmail Password
    dabom · 2010-01-31 00:44:35 45
  • Turn shell tracing and verbosity (set -xv) on/off with 1 command!

    Turn shell tracing and verbosity (set -xv) on/off in any Bourne-type shell If either -x or -v is set, the function turns them both off. If neither is on, both are turned on.


    4
    xv() { case $- in *[xv]*) set +xv;; *) set -xv ;; esac }
    cfajohnson · 2010-02-14 20:57:29 3
  • Count number of hits per IP address in last 2000 lines of apache logs and print the IP and hits if hits > 20


    4
    tail -n2000 /var/www/domains/*/*/logs/access_log | awk '{print $1}' | sort | uniq -c | sort -n | awk '{ if ($1 > 20)print $1,$2}'
    allrightname · 2010-05-10 19:08:37 3
  • Short one line while loop that outputs parameterized content from one file to another


    4
    awk '{print $1}' < three-column.txt > first-column.txt
    infinull · 2010-07-09 04:00:05 5
  • Short one line while loop that outputs parameterized content from one file to another

    There is a common command for outputting a field or list of fields from each line in a file. Why wouldn't you just use cut?


    4
    cut -f 1 three-column.txt > first-column.txt
    postrational · 2010-07-11 10:13:45 5
  • Command line calculator

    works with fractions like 1/3.5


    4
    awk "BEGIN{ print $* }"
    maelcum · 2010-10-07 16:13:41 7
  • move cursor to beginning of command line

    Pressing Ctrl combined with 'a' will move the cursor to the beginning of the command under bash (other shells?). I used to do this after arrowing up for the last command, then typing 'sudo ' to run the last command as root, but of course the all time greatest command here `sudo !!` is more succinct. Still Ctrl+A can be very useful when you want to edit something at/close to the beginning of the command line.


    4
    Ctrl+a
    jemptymethod · 2010-10-11 16:02:57 13
  • Debug SSH at the Maximum Verbosity Level

    When debugging an ssh connection either to optimize your settings ie compression, ciphers, or more commonly for debugging an issue connecting, this alias comes in real handy as it's not easy to remember the '-o LogLevel=DEBUG3' argument, which adds a boost of debugging info not available with -vvv alone. Especially useful are the FD info, and the setup negotiation to create a cleaner, faster connection. Show Sample Output


    4
    alias sshv='ssh -vvv -o LogLevel=DEBUG3'
    AskApache · 2010-10-30 11:23:52 4
  • Console clock

    Turn your terminal into digital clock. Show Sample Output


    4
    while [[ 1 ]] ; do clear; banner `date +%H:%M:%S` ; sleep 1; done
    lkj · 2011-03-24 16:41:09 5
  • cd into another dir to run a one-liner, but implicitly drop back to your $OLD_PWD after

    Obviously the example given is necessarily simple, but this command not only saves time on the command line (saves you using "cd -" or, worse, having to type a fully qualified path if your command cd's more than once), but is vital in scripts, where I've found the behaviour of "cd -" to be a little broken at times. Show Sample Output


    4
    ( cd $DIR; command; )
    sanmiguel · 2011-03-29 13:16:00 7
  • ThePirateBay.org torrent search

    This one-liner greps first 30 direct URLs for .torrent files matching your search querry, ordered by number of seeds (descending; determined by the second number after your querry, in this case 7; for other options just check the site via your favorite web-browser). You don't have to care about grepping the torrent names as well, because they are already included in the .torrent URL (except for spaces and some other characters replaced by underscores, but still human-readable). Be sure to have some http://isup.me/ macro handy (someone often kicks the ethernet cables out of their servers ;) ). I've also coded a more user-friendly ash (should be BASH compatible) script, which also lists the total size of download and number of seeds/peers (available at http://saironiq.blogspot.com/2011/04/my-shell-scripts-4-thepiratebayorg.html - may need some tweaking, as it was written for a router running OpenWrt and transmission). Happy downloading!


    4
    wget -U Mozilla -qO - "http://thepiratebay.org/search/your_querry_here/0/7/0" | grep -o 'http\:\/\/torrents\.thepiratebay\.org\/.*\.torrent'
    sairon · 2011-04-15 15:01:16 30
  • Multiple variable assignments from command output in BASH

    It's quite easy to capture the output of a command and assign it in a shell's variable: day=$(date +%d) month=$(date +%m) But, what if we want to perform the same task with just one program invocation? Here comes the power of eval! date(1) outputs a string like "day=29; month=07; year=11" (notice the semicolons I added on purpose at date's custom output) which is a legal shell line. This like is then parsed and executed by the shell once again with the help of eval. Just setting 3 variables! Inspired by LinuxJournal's column "Dave Taylor's Work the Shell". Show Sample Output


    4
    eval $(date +"day=%d; month=%m; year=%y")
    xakon · 2011-07-29 12:47:26 19
  • ThePirateBay.org torrent search

    usage: tpb searchterm example: tpb the matrix trilogy This searches for torrents from thepiratebay and displays the top results in reverse order, so the 1st result is at the bottom instead of the top -- which is better for command line users


    4
    tpb() { wget -U Mozilla -qO - $(echo "http://thepiratebay.org/search/$@/0/7/0" | sed 's/ /\%20/g') | grep -o 'http\:\/\/torrents\.thepiratebay\.org\/.*\.torrent' | tac; }
    Bonster · 2011-10-26 12:15:55 28
  • convert from decimal to hexadecimal

    Use the standard calculator bc to convert decimals to hex Show Sample Output


    4
    hex() { bc <<< "obase=16; $1"; }
    bjomape · 2011-12-09 13:57:05 11
  • Find out if a module is installed in perl

    Shows the path if the module is installed or exit quietly (to simply avoid the 'No documentation found' msg). Show Sample Output


    4
    perldoc -l Module::Name 2>/dev/null
    MarxBro · 2013-01-11 23:28:13 10
  • bash auto-complete your screen sessions

    this bash command sets it so that when you type "screen ", it searches your running screens, and present valid auto-complete choices. The output is . Note: You must have programmable completion enabled. Check with "shopt progcomp", set with "shopt -s progcomp" Show Sample Output


    4
    complete -C "perl -e '@w=split(/ /,\$ENV{COMP_LINE},-1);\$w=pop(@w);for(qx(screen -ls)){print qq/\$1\n/ if (/^\s*\$w/&&/(\d+\.\w+)/||/\d+\.(\$w\w*)/)}'" screen
    hubt · 2013-04-10 17:17:33 6
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Convert filenames from ISO-8859-1 to UTF-8
Nothing advanced, it just finds filenames that are stored with ISO-8859-1 characters and and converts those into UTF-8. Recommended to use without the --notest flag first so you can see what will be changed.

display a smiling smiley if the command succeeded and a sad smiley if the command failed
you could save the code between if and fi to a shell script named smiley.sh with the first argument as and then do a smiley.sh to see if the command succeeded. a bit needless but who cares ;)

Save a copy of all debian packages in the form in which they are installed and configured on your system
A copy of all installed debian packages on your system will be put back together, with all changes in configuration files you made and placed in the current directory. Make sure you have enough disk space (say 2-3 GB). Break any time with Ctrl+C.

Remotely sniff traffic and pass to snort
I have a small embedded linux device that I wanted to use for sniffing my external network, but I didn't want to recompile/cross-compile snort for the embedded platform. So I used tcpdump over ssh to pass all the traffic as pcap data to a "normal" Linux system that then takes the pcap data and passes it to snort for processing.

Create executable, automountable filesystem in a file, with password!
This is just a proof of concept: A FILE WHICH CAN AUTOMOUNT ITSELF through a SIMPLY ENCODED script. It takes advantage of the OFFSET option of mount, and uses it as a password (see that 9191? just change it to something similar, around 9k). It works fine, mounts, gets modified, updated, and can be moved by just copying it. USAGE: SEE SAMPLE OUTPUT The file is composed of three parts: a) The legible script (about 242 bytes) b) A random text fill to reach the OFFSET size (equals PASSWORD minus 242) c) The actual filesystem Logically, (a)+(b) = PASSWORD, that means OFFSET, and mount uses that option. PLEASE NOTE: THIS IS NOT AN ENCRYPTED FILESYSTEM. To improve it, it can be mounted with a better encryption script and used with encfs or cryptfs. The idea was just to test the concept... with one line :) It applies the original idea of http://www.commandlinefu.com/commands/view/7382/command-for-john-cons for encrypting the file. The embedded bash script can be grown, of course, and the offset recalculation goes fine. I have my own version with bash --init-file to startup a bashrc with a well-defined environment, aliases, variables.

ping a range of IP addresses
nmap accepts a wide variety of addressing notation, multiple targets/ranges, etc.

Create test images
Useful to test programs and webpages.

Join the content of a bash array with commas
$ DOCKER_APP_VARS=(DATABASE_USER=dbuserro, DATABASE_PASSWORD=maipass) [jeff@omniscience container] (master)$ echo docker run $(printf -- " -e %s" ${DOCKER_APP_VARS[*]}) -name 12factorapp mattdm/fedora-small docker run -e DATABASE_USER=dbuserro, -e DATABASE_PASSWORD=maipass -name 12factorapp mattdm/fedora-small Note that the printf method by itsself doesn't include a newline (\n), so you'll need to embed it into an echo statement or something that does.

Sets shell timeout
Useful in root's .profile - will auto-logout after TMOUT seconds of inactivity. Close after `seconds` inactive. export TMOUT=seconds (unefunge)

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

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