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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

Top Tags



Psst. Open beta.

Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:

  • » The open beta is running a copy of the database that will not carry over to the final version. Don't post anything you don't mind losing.
  • » If you wish to use your user account, you will probably need to reset your password.
Your feedback is appreciated via the form on the beta page. Thanks! -Jon & CLFU Team

Commands using echo from sorted by
Terminal - Commands using echo - 1,326 results
echo $(( `ulimit -u` - `find /proc -maxdepth 1 \( -user $USER -o -group $GROUPNAME \) -type d|wc -l` ))
2010-03-12 08:42:49
User: AskApache
Functions: echo wc

There is a limit to how many processes you can run at the same time for each user, especially with web hosts. If the maximum # of processes for your user is 200, then the following sets OPTIMUM_P to 100.

OPTIMUM_P=$(( (`ulimit -u` - `find /proc -maxdepth 1 \( -user $USER -o -group $GROUPNAME \) -type d|wc -l`) / 2 ))

This is very useful in scripts because this is such a fast low-resource-intensive (compared to ps, who, lsof, etc) way to determine how many processes are currently running for whichever user. The number of currently running processes is subtracted from the high limit setup for the account (see limits.conf, pam, initscript).

An easy to understand example- this searches the current directory for shell scripts, and runs up to 100 'file' commands at the same time, greatly speeding up the command.

find . -type f | xargs -P $OPTIMUM_P -iFNAME file FNAME | sed -n '/shell script text/p'

I am using it in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html especially for the xargs command. Xargs has a -P option that lets you specify how many processes to run at the same time. For instance if you have 1000 urls in a text file and wanted to download all of them fast with curl, you could download 100 at a time (check ps output on a separate [pt]ty for proof) like this:

cat url-list.txt | xargs -I '{}' -P $OPTIMUM_P curl -O '{}'

I like to do things as fast as possible on my servers. I have several types of servers and hosting environments, some with very restrictive jail shells with 20processes limit, some with 200, some with 8000, so for the jailed shells my xargs -P10 would kill my shell or dump core. Using the above I can set the -P value dynamically, so xargs always works, like this.

cat url-list.txt | xargs -I '{}' -P $OPTIMUM_P curl -O '{}'

If you were building a process-killer (very common for cheap hosting) this would also be handy.

Note that if you are only allowed 20 or so processes, you should just use -P1 with xargs.

echo "ulimit `ulimit -a|sed -e 's/^.*\([a-z]\))\(.*\)$/-\1\2/'|tr "\n" ' '`"
2010-03-12 06:46:54
User: AskApache
Functions: echo

It is helpful to know the current limits placed on your account, and using this shortcut is a quick way to figuring out which values to change for optimization or security.

Alias is:

alias ulimith="command ulimit -a|sed 's/^.*\([a-z]\))\(.*\)$/-\1\2/;s/^/ulimit /'|tr '\n' ' ';echo"

Here's the result of this command:

ulimit -c 0 -d unlimited -e 0 -f unlimited -i 155648 -l 32 -m unlimited -n 8192 -p 8 -q 819200 -r 0 -s 10240 -t unlimited -u unlimited -v unlimited -x unlimited ulimit -a

core file size (blocks, -c) 0

data seg size (kbytes, -d) unlimited

scheduling priority (-e) 0

file size (blocks, -f) unlimited

pending signals (-i) 155648

max locked memory (kbytes, -l) 32

max memory size (kbytes, -m) unlimited

open files (-n) 8192

pipe size (512 bytes, -p) 8

POSIX message queues (bytes, -q) 819200

real-time priority (-r) 0

stack size (kbytes, -s) 10240

cpu time (seconds, -t) unlimited

max user processes (-u) unlimited

virtual memory (kbytes, -v) unlimited

file locks (-x) unlimited

function setTerm() { PROFILE=${1}; echo "tell app \"Terminal\" to set current settings of first window to settings set \"${PROFILE}\""|osascript; };
gofuckanalytics() { echo "DELETE FROM moz_cookies WHERE name LIKE '__utm%';" | sqlite3 $( find ~/.mozilla -name cookies.sqlite ) }
2010-03-07 09:16:14
User: meathive
Functions: echo find

See http://code.google.com/apis/analytics/docs/concepts/gaConceptsCookies.html if you are unclear about the Google Analytics cookie system. If Firefox is your daily browser, be a good Orwellian and run this command regularly.

If you see, 'SQL error near line 1: database is locked', close Firefox and run again.

file -L <library> | grep -q '64-bit' && echo 'library is 64 bit' || echo 'library is 32 bit'
2010-03-07 06:31:35
User: infinull
Functions: echo file grep
Tags: bash

file displays a files type

the -L flag means follow sym-links (as libraries are often sym-linked to another this behavior is likely preferred)

more complex behavior (*two* grep commands!) could be used to determine if the file is or is not a shared library.

libquery=/lib32/libgcc_s.so.1; if [ `nm -D $libquery | sed -n '/[0-9A-Fa-f]\{8,\}/ {p; q;}' | grep "[0-9A-Fa-f]\{16\}" | wc -l` == 1 ]; then echo "$libquery is a 64 bit library"; else echo "$libquery is a 32 bit library"; fi;
2010-03-07 04:24:08
User: birnam
Functions: echo grep sed wc
Tags: bash nm

Determines the flavor of a shared library by looking at the addresses of its exposed functions and seeing if they are 16 bytes or 8 bytes long. The command is written so the library you are querying is passed to a variable up font -- it would be simple to convert this to a bash function or script using this format.

(echo "" | xsel -o) ; (programa | wgetpaste -s dpaste | awk '{print $7}' | xsel -ai)
2010-03-05 09:31:30
User: dvinchi666
Functions: awk echo
Tags: pipes paste

manda la salida de un comando hacia un servicio de paste y coloca la url de ese paste en el portapapeles

echo sortmeplease | perl -pe 'chomp; $_ = join "", sort split //'
while read f;do echo "$f";done < <(find .)
2010-03-02 14:22:22
Functions: echo find read

Read all contents from current directory and display to stdout.

find . |while read f;do echo "$f";done
2010-03-02 14:21:15
Functions: echo find read

Read all contents from current directory and display it on stdout.

find . type f -exec echo http://exg.com/{} \; > file
2010-03-02 14:18:01
Functions: echo find type

find all files in cur dir add to url and append to file

echo "message" | smbclient -M NAME_OF_THE_COMPUTER
2010-02-28 21:10:46
User: mvrilo
Functions: echo

It will only work if the service NETSEND in the Windows machine is enabled.

psgrep() { if [ ! -z $1 ]; then echo "Grepping for processes matching $1..." ps aux | grep -i $1 | grep -v grep; else echo "!! Need name to grep for"; fi }
2010-02-27 13:47:28
User: evenme
Functions: echo grep ps
Tags: grep ps

Grep for a named process.

TOTAL_RAM=`free | head -n 2 | tail -n 1 | awk '{ print $2 }'`; PROC_RSS=`ps axo rss,comm | grep [h]ttpd | awk '{ TOTAL += $1 } END { print TOTAL }'`; PROC_PCT=`echo "scale=4; ( $PROC_RSS/$TOTAL_RAM ) * 100" | bc`; echo "RAM Used by HTTP: $PROC_PCT%"
2010-02-26 20:29:45
User: d34dh0r53
Functions: awk echo grep head tail

Change the name of the process and what is echoed to suit your needs. The brackets around the h in the grep statement cause grep to skip over "grep httpd", it is the equivalent of grep -v grep although more elegant.

box(){ c=${2-=}; l=$c$c${1//?/$c}$c$c; echo -e "$l\n$c $1 $c\n$l"; unset c l;}
2010-02-26 17:14:52
User: mightybs
Functions: c++ echo unset
Tags: bash echo

First argument: string to put a box around.

Second argument: character to use for box (default is '=')

Same as command #4962, cleaned up, shortened, and more efficient. Now a ' * ' can be used as the box character, and the variables get unset so they don't mess with anything else you might have.

They marked c++ as a function for this command, but I'm not sure why. Must be a bug.

box() { t="$1xxxx";c=${2:-=}; echo ${t//?/$c}; echo "$c $1 $c"; echo ${t//?/$c}; }
2010-02-26 13:17:12
User: bartonski
Functions: echo

First argument: string to put a box around.

Second argument: character to use for box (default is '=')

Same as command #4948, but shorter, and without the utility function.

box() { l=${#1}+4;x=${2:-=};n $l $x; echo "$x $1 $x"; n $l $x; }; n() { for (( i=0; $i<$1; i=$i+1)); do printf $2; done; printf "\n"; }
2010-02-26 06:56:59
User: bartonski
Functions: echo printf

The function 'box' takes either one or two arguments. The first argument is a line of text to be boxed, the second argument (optional) is a character to use to draw the box. By default, the drawing character will be '='.

The function 'n()' is a helper function used to draw the upper and lower lines of the box, its arguments are a length, and an character to print. (I used 'n' because 'line', 'ln' and 'l' are all commonly used)

underline() { echo $1; for (( i=0; $i<${#1}; i=$i+1)); do printf "${2:-=}"; done; printf "\n"; }
2010-02-26 05:46:49
User: bartonski
Functions: echo printf

underline() will print $1, followed by a series of '=' characters the width of $1. An optional second argument can be used to replace '=' with a given character.

This function is useful for breaking lots of data emitted in a for loop into sections which are easier to parse visually. Let's say that 'xxxx' is a very common pattern occurring in a group of CSV files.

You could run

grep xxxx *.csv

This would print the name of each csv file before each matching line, but the output would be hard to parse visually.

for i in *.csv; do printf "\n"; underline $i; grep "xxxx" $i; done

Will break the output into sections separated by the name of the file, underlined.

echo -e "Some Text Line1\nSome Text Line 2" | convert -background none -density 196 -resample 72 -unsharp 0x.5 -font "Courier" text:- -trim +repage -bordercolor white -border 3 text.gif
2010-02-25 18:58:42
User: glaudiston
Functions: echo

generates a picture file with the text.

Some other samples in:


echo "pretty realistic virtual typing" | randtype -m 4
2010-02-25 15:30:28
User: tehdog
Functions: echo

this also generates errors (change 4 to higher number for more mistakes)

{ u="http://twitter.com/commandlinefu"; echo "Subject: $u"; echo "Mime-Version: 1.0"; echo -e "Content-Type: text/html; charset=utf-8\n\n"; curl $u ; } | sendmail [email protected]
2010-02-24 04:18:30
User: pascalv
Functions: echo sendmail

This will send the web page at $u to [email protected] . To send the web page to oneself, [email protected] can be replaced by $(whoami) .

The "charset" is UTF-8 here, but any alternative charset of your choice would work.

`wget -O - -o /dev/null $u` may be considered instead of `curl $u` .

On some systems the complete path to sendmail may be necessary, for instance /sys/pkg/libexec/sendmail/sendmail for some NetBSD.

echo "Starting Daemon"; ( while :; do sleep 15; echo "I am still running =]"; done ) & disown -h $!
2010-02-23 19:17:05
User: daleki
Functions: echo sleep

You don't want the -ar parameters in this case. The man page for BASH_BUILTINS(1) states:

"-a option means to remove or mark all jobs" and

"-r option without a jobspec argument restricts operation to running jobs"

In this case we are supplying the process id of the job to disown so neither of these should be used.

echo 0 >/selinux/enforce
2010-02-17 16:33:26
User: svnlabs
Functions: echo

just change SELINUX=enforcing to SELINUX=permissive, and you're done. Reboot if you want to prove it.

spellcheck(){ typeset y=$@;curl -sd "<spellrequest><text>$y</text></spellrequest>" https://www.google.com/tbproxy/spell|sed -n '/s="[0-9]"/{s/<[^>]*>/ /g;s/\t/ /g;s/ *\(.*\)/Suggestions: \1\n/g;p}'|tee >(grep -Eq '.*'||echo -e "OK");}
2010-02-17 08:20:48
User: eightmillion
Functions: echo grep sed tee

I took matthewbauer's cool one-liner and rewrote it as a shell function that returns all the suggestions or outputs "OK" if it doesn't find anything wrong. It should work on ksh, zsh, and bash. Users that don't have tee can leave that part off like this:

spellcheck(){ typeset y=$@;curl -sd "<spellrequest><text>$y</text></spellrequest>" https://google.com/tbproxy/spell|sed -n '/s="[1-9]"/{s/<[^>]*>/ /g;s/\t/ /g;s/ *\(.*\)/Suggestions: \1\n/g;p}';}
for domain in `cat list_of_domains.txt`; do echo $domain; whois $domain >> output.txt; done
2010-02-15 17:13:45
User: pathcl
Functions: echo whois

Outputs multiple whois from a plain text file.