Hide

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

OpenID
or
Sign in Register

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Hide

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Hide

Credits

Site by David Winterbottom (user root).

Commands using head

Commands using head from sorted by
Terminal - Commands using head - 195 results
wget --no-use-server-timestamps $(curl $(curl http://wallbase.cc/random/23/eqeq/1920x1080/0/100/20 | grep 'wallpaper/' | awk -F'"' '{print $2}' | head -n1) | grep -A4 bigwall | grep img | awk -F'"' '{print $2}'); feh --bg-center $(ls -1t | head -n1)
2012-08-14 22:06:27
User: yosh
Functions: awk grep head ls wget
0
Up
Down
Random (sfw, 1920x1080) wallpaper from wallbase.cc
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
vlc $(for f in /proc/$(pgrep -f libflashplayer.so |head -n 1)/fd/*; do ;if $(file ${f} |grep -q "broken symbolic link to \`/tmp/FlashXX"); then echo ${f};fi;done)
2012-08-07 08:04:56
User: rtaycher
Functions: echo file grep head
0
Up
Down
Opens up cached flash plugin video files(linux)
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
find . -type f -exec ls -shS {} + | head -10
2012-07-28 17:21:46
User: erichamion
Functions: find head ls
Tags: sort find GNU find file size
0
Up
Down
Find biggest 10 files in current and subdirectories and sort by file size

This requires a version of GNU find that supports the -exec {} + action, but it seems more straightforward than the versions already posted.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
for i in {1..10};do wget $(wget -O- -U "" "http://images.google.com/images?imgsz=xxlarge&hl=en&q=wallpaper+HD&start=$(($RANDOM%900+100))" --quiet | grep -oe 'http://[^"]*\.jpg' | head -1);done
2012-07-26 10:42:13
User: dzup
Functions: grep head wget
6
Up
Down
download 10 random wallpapers from google

you may want &hl=en for &hl=es for the language

you may want imgsz=xxlarge for imgsz=large or whatever filter

you may want q=apples or whatever

Comments (6) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ip a s eth0 | grep "inet " | head -n 1 | awk '{print $2}' | cut -f1 -d'/'
2012-07-16 07:54:43
User: thelan
Functions: awk cut grep head
Tags: IP
-4
Up
Down
Get the IP address

Get the first IPv4 address of an interface

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
systemctl --failed | head -n -6 | tail -n -1
2012-07-11 22:31:46
User: corpix
Functions: head tail
0
Up
Down
Print failed units in systemd
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
SEED=$(head -1 /dev/urandom|od -N 1);for i in {1..10};do tmp=$(mkpasswd ${RANDOM});pass=${tmp:2:6};echo Pass $pass Crypt: $(mkpasswd $pass);done
2012-07-07 03:20:46
User: dzup
Functions: echo head od
0
Up
Down
Show 10 6 characters pass and crypt(3) *if you like
Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
find . -type f -print0 | xargs -0 du -h | sort -hr | head -10
2012-06-30 10:03:31
User: netaxiz
Functions: du find head sort xargs
Tags: sort find file size
8
Up
Down
Find biggest 10 files in current and subdirectories and sort by file size
Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
curl -s kernel.org | grep '<strong>' | head -3 | tail -1 | cut -d'>' -f3 | cut -d'<' -f1
2012-06-15 21:28:42
User: mdix
Functions: cut grep head tail
0
Up
Down
Get current stable kernel version string from kernel.org
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ps -e h -o pid --sort -pcpu | head -10 | vzpid -
2012-05-24 14:16:40
User: mrkmg
Functions: head ps
Tags: openvz
0
Up
Down
See OpenVZ Container id's of top 10 running processes by %cpu

This command will list the PID, VEID, and Name of the 10 highest cpu using processes on a openvz host. You must have vzpid installed.

Show sample output | Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
wget -O - http://www.reddit.com/r/wallpapers.rss | grep -Eo 'http://i.imgur.com[^&]+jpg' | head -1 | xargs wget -O background.jpg
2012-04-25 11:15:26
User: untitaker
Functions: grep head wget xargs
0
Up
Down
set desktop background to highest-rated image from Reddit /r/wallpapers

Doesn't depend on curl and doesn't use thumbnails as wallpaper (which has the unfortunate effect of only allowing imgur links)

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
(set -o noglob;while sleep 0.05;do for r in `grep -ao '[[:print:]]' /dev/urandom|head -$((COLUMNS/3))`;do [ $((RANDOM%6)) -le 1 ] && r=\ ;echo -ne "\e[$((RANDOM%7/-6+2));32m $r ";done;echo;done)
2012-04-13 02:09:10
User: khopesh
Functions: echo head set sleep
Tags: color screensaver Matrix Matrix Style
0
Up
Down
Matrix Style

A tweak using Patola's code as a base, this full-width green matrix display has all the frills (and all the printable characters).

You don't need the surrounding parens if you don't care about losing globbing capabilities. Z-shell (/bin/zsh) needs neither the parens nor the `set -o noglob`

Screen shot (animated): http://desmond.imageshack.us/Himg32/scaled.php?server=32&filename=matrixh.gif&res=landing

If it's too slow, try lowering the `sleep 0.05` or even replacing it with `true` (which is faster than `sleep 0`).

I squashed it as narrow as I could to conserve space, though somebody could probably squeeze a char or two out.

Enjoy!

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
find . -type f -print0 | xargs -0 du -h | sort -hr | head -20
2012-03-30 10:21:12
User: flatcap
Functions: du find head sort xargs
Tags: sort find du xargs head,
6
Up
Down
Recursively find top 20 largest files (> 1MB) sort human readable format

Search for files and list the 20 largest.

find . -type f

gives us a list of file, recursively, starting from here (.)

-print0 | xargs -0 du -h

separate the names of files with NULL characters, so we're not confused by spaces

then xargs run the du command to find their size (in human-readable form -- 64M not 64123456)

| sort -hr

use sort to arrange the list in size order. sort -h knows that 1M is bigger than 9K

| head -20

finally only select the top twenty out of the list

Show sample output | Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
head -n1 nation.tbl | sed 's/\(.\)/\1\n/g' | sort | uniq -c | grep \| | awk '{ print $1 }'
2012-03-03 12:35:58
User: maarten
Functions: awk grep head sed sort uniq
0
Up
Down
Count Number of Columns in TPC-H table-file (or any pipe seperated file
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
sed -e 's/[;|][[:space:]]*/\n/g' .bash_history | cut --delimiter=' ' --fields=1 | sort | uniq --count | sort --numeric-sort --reverse | head --lines=20
2012-02-17 23:34:16
User: WissenForscher
Functions: cut head sed sort uniq
Tags: bash sort sed uniq
1
Up
Down
Top 20 commands in your bash history
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
for i in $(ps -eo pid,pmem,pcpu| sort -k 3 -r|grep -v PID|head -10|awk '{print $1}');do diff -yw <(pidstat -p $i|grep -v Linux) <(ps -o euser,pri,psr,pmem,stat -p $i|tail);done
2012-02-16 20:54:32
User: bob_the_builder
Functions: awk diff grep head ps sort
0
Up
Down
Displays user-defined ps output and pidstat output about the top CPU or MEMory users.

It grabs the PID's top resource users with $(ps -eo pid,pmem,pcpu| sort -k 3 -r|grep -v PID|head -10)

The sort -k is sorting by the third field which would be CPU. Change this to 2 and it will sort accordingly.

The rest of the command is just using diff to display the output of 2 commands side-by-side (-y flag) I chose some good ones for ps.

pidstat comes with the sysstat package(sar, mpstat, iostat, pidstat) so if you don't have it, you should.

I might should take off the timestamp... :|

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
export GREP_COLOR='1;32';while [ true ]; do head -n 100 /dev/urandom; sleep .1; done | hexdump -C | grep --color=auto "ca fe"
2012-02-14 19:30:03
User: tbaschak
Functions: export grep head hexdump sleep true
1
Up
Down
pretend to be busy in office to enjoy a cup of coffee

combination of several of the above

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ls -t1 $* | head -1 ;
2012-02-10 22:13:24
User: darkhorse9933
Functions: head ls
Tags: alias directory files
0
Up
Down
A bash function to show the files most recently modified in the named (or current) directory

Returns the most recently modified file in the current (or specified) directory. You can also get the oldest file, via:

ls -t1 $* | tail-1 ;

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
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%"
2012-02-03 16:10:36
User: 0disse0
Functions: awk echo grep head tail
Tags: memory usage process
0
Up
Down
display memory usage of a process

page where I got inspiration:

http://www.commandlinefu.com/commands/view/5473/get-acurate-memory-usage-of-a-process-in-megabytes

and

http://www.commandlinefu.com/commands/view/10022/display-the-top-10-running-processes-sorted-by-memory-usage

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
while true; do curl -s http://sensiblepassword.com/?harder=1 | tail -n 15 | head -n 1 | sed 's;<br/>;;' | cut -c 5- | cb; sleep 1; done
2012-01-30 20:52:14
User: supervacuo
Functions: cut head sed sleep tail
Tags: copy paste website password clipboard generator generate
1
Up
Down
Generate random sensible passwords, and copy them to the clipboard

Use the excellent sensiblepasswords.com to a generate random (yet easy-to-remember) password every second, and copy it to the clipboard. Useful for generating a list of passwords and pasting them into a spreadsheet.

This script uses "madebynathan"'s "cb" function (http://madebynathan.com/2011/10/04/a-nicer-way-to-use-xclip/); you could also replace "cb" with

xclip -selection c

Remove "while true; do" and "; done" to generate and copy only 1 password.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
PID=`ps | grep process_name | grep -v grep | head -n 1 | awk '{print $1}'`; cat /proc/$PID/smaps | grep heap -A 2
2012-01-30 13:31:40
User: yohananov
Functions: awk cat grep head
Tags: proc
0
Up
Down
Print heap addresses and size
Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
grep . "$f" | head -n1
2012-01-27 02:58:07
User: captaincomic
Functions: grep head
Tags: grep
0
Up
Down
Get the first non-empty line in a text file

Use this command if your file may contain empty lines and you need to optain the first non-empty line.

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
genRandomText() { cat /dev/urandom|tr -dc 'a-zA-Z'|head -c $1 }
2012-01-21 00:51:34
User: thomasba
Functions: cat head tr
Tags: random urandom
0
Up
Down
Generate Random Text based on Length

Using urandom to get random data, deleting non-letters with tr and print the first $1 bytes.

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
cat /dev/urandom | tr -dc A-Za-z0-9 | head -c 32
2011-11-20 17:29:45
User: noqqe
Functions: cat head tr
8
Up
Down
Generate a random password 30 characters long
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
memnum=$(awk '{ print $2 }' /proc/meminfo |head -n1); echo "$memnum / 1024 / 1024" | bc -l
2011-11-08 16:28:25
User: wekoch
Functions: awk bc echo head
-2
Up
Down
Get memory total from /proc/meminfo in Gigs

Probably more trouble than its worth, but worked for the obscure need.

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate