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.

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

Universal configuration monitoring and system of record for IT.

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:



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





Commands tagged Linux from sorted by
Terminal - Commands tagged Linux - 237 results
ls | grep *.txt | while read file; do cat $file >> ./output.txt; done;
wget randomfunfacts.com -O - 2>/dev/null | grep \<strong\> | sed "s;^.*<i>\(.*\)</i>.*$;\1;" | while read FUNFACT; do notify-send -t $((1000+300*`echo -n $FUNFACT | wc -w`)) -i gtk-dialog-info "RandomFunFact" "$FUNFACT"; done
2010-04-02 09:43:32
User: mtron
Functions: grep read sed wc wget

extension to tali713's random fact generator. It takes the output & sends it to notify-osd. Display time is proportional to the lengh of the fact.

wget randomfunfacts.com -O - 2>/dev/null | grep \<strong\> | sed "s;^.*<i>\(.*\)</i>.*$;\1;"
2010-03-30 23:49:30
User: tali713
Functions: grep sed wget

Though without infinite time and knowledge of how the site will be designed in the future this may stop working, it still will serve as a simple straight forward starting point.

This uses the observation that the only item marked as strong on the page is the single logical line that includes the italicized fact.

If future revisions of the page show failure, or intermittent failure, one may simply alter the above to read.

wget randomfunfacts.com -O - 2>/dev/null | tee lastfact | grep \<strong\> | sed "s;^.*<i>\(.*\)</i>.*$;\1;"

The file lastfact, can then be examined whenever the command fails.

sed -i 's/20[0-1][0-9]\{7\}/'`date +%Y%m%d%I`'/g' *.db
2010-03-24 07:28:58
User: alf
Functions: sed

Will edit *.db files in the same directory with todays date. Useful for doing a mass update to domains on a nameserver, adding spf records, etc.

Looks for a string starting with 200 or 201 followed by 7 numbers, and replaces with todays date. This won't overwrite Ip's but i would still do some double checking after running this.

Make sure your server's date is correct, otherwise insert your own serial number.

rndc reload

should usually follow this command.

if [ "$(ping -q -c1 google.com)" ];then wget -mnd -q http://www.google.com/intl/en_ALL/images/logo.gif ;fi
2010-03-23 04:15:03
User: alf
Functions: wget

Bash scrip to test if a server is up, you can use this before wget'ing a file to make sure a blank one isn't downloaded.

sleep 3 && xdotool type --delay 0ms texthere
2010-02-18 11:44:18
User: drinkcat
Functions: sleep type
Tags: Linux

Just after you type enter, you have 3 seconds to switch window, then "texthere" will be "typed" in the X11 application that has focus. Very useful to beat your score at games such as "How fast can you type A-Z".

DISPLAY=":0.0" import -window root screenshot.png
2010-02-17 13:02:24
User: walterl

The `export` is unnecessary if it's only applicable to the one command.

export DISPLAY=":0.0" && import -window root screenshot.png
2010-02-17 12:13:49
User: fraktil
Functions: export

Like the given command, but combines _DISPLAY=":0.0"_ with _export DISPLAY_ to get _export DISPLAY=":0.0"_ and only imports if DISPLAY is set successfully.

ffmpeg -i /var/lib/mythtv/pretty/Chuck20100208800PMChuckVersustheMask.mpg -s 800x480 -vcodec mpeg4 -acodec libfaac -ac 2 -ar 16000 -r 13 -ab 32000 -aspect 16:9 Chuck20100208800PMChuckVersustheMask.mp4
2010-02-12 12:11:02
User: PLA

This command will transcode a MythTV recording. The target device is a Google Nexus One mobile phone. My recordings are from a HDHomerun with Over The Air content. Plays back nicely on the N1.

for i in $(ps -ef | awk '{print $2}') ; { swp=$( awk '/Swap/{sum+=$2} END {print sum}' /proc/$i/smaps ); if [[ -n $swp && 0 != $swp ]] ; then echo -n "\n $swp $i "; cat /proc/$i/cmdline ; fi; } | sort -nr
lgrep() { string=$1; file=$2; awk -v String=${string} '$0 ~ String' ${file}; }
2010-01-19 09:42:19
User: dopeman
Functions: awk

This is a handy way to circumvent the "Maximum line length of 2048 exceeded" grep error.

Once you have run the above command (or put it in your .bashrc), files can be searched using:

lgrep search-string /file/to/search
sudo nmap -F -O | grep "Running: " > /tmp/os; echo "$(cat /tmp/os | grep Linux | wc -l) Linux device(s)"; echo "$(cat /tmp/os | grep Windows | wc -l) Window(s) devices"
2010-01-10 03:09:56
User: matthewbauer
Functions: echo grep sudo

Shows how many Windows and Linux devices are on your network.

May add support for others, but that's all that are on my network right now.

gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=OUTPUT.pdf -c .setpdfwrite -f INPUT.pdf
2009-12-14 21:30:22
User: deijmaster
Functions: gs

Remove security from PDF document using this very simple command on Linux and OSX. You need ghostscript for this baby to work.

iconv -f utf8 -t utf16 /path/to/file
utime(){ perl -e "print localtime($1).\"\n\"";}
2009-11-06 12:58:10
User: MoHaG
Functions: perl

A shell function using perl to easily convert Unix-time to text.

Put in in your ~/.bashrc or equivalent.

Tested on Linux / Solaris Bourne, bash and zsh. using perl 5.6 and higher.

(Does not require GNU date like some other commands)

iscsiadm -m node -l
iscsiadm -m discovery -t sendtargets -p
sudo touch /forcefsck
2009-10-29 17:04:47
User: johnraff
Functions: sudo touch

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
pwgen --alt-phonics --capitalize 9 10
2009-10-24 08:36:36
User: CafeNinja
Tags: Linux terminal

Produces secure passwords that satisfy most rules for secure passwords and can be customized for correct output as needed. See "man pwgen" for details.

echo -e "n\np\n1\n\n\nt\n8e\nw" | fdisk /dev/sdX
2009-10-20 16:21:54
User: sud0er
Functions: echo fdisk
Tags: Linux fdisk

This is a bit hacky, but if you're setting up a bunch of new LUNs, it can save a bunch of time. Also check out sfdisk. The fdisk will fail if, for example, a partition table already exists.

netstat -ltun
2009-10-05 08:39:03
User: Decoy
Functions: netstat

Works only on Linux.

Last option (n) turn name of service resolving (/etc/services) off.

socat -v tcp4-l:<port> tcp4:<host>:<port>
gate() { mkfifo /tmp/sock1 /tmp/sock2 &> /dev/null && nc -p $1 -l < /tmp/sock1 | tee /tmp/sock2 & PID=$! && nc $2 $3 < /tmp/sock2 | tee /tmp/sock1; kill -KILL $PID; rm -f /tmp/sock1 /tmp/sock2 ; }
2009-09-25 08:10:23
User: true
Functions: kill mkfifo rm tee

USAGE: gate listening_port host port

Creates listening socket and connects to remote device at host:port. It uses pipes for connection between two sockets. Traffic which goes through pipes is wrote to stdout. I use it for debug network scripts.

find . \( ! -name . -prune \) \( -type f -o -type l \)
2009-09-12 15:58:56
User: mobidyc
Functions: find

you must be in the directory to analyse

report all files and links in the currect directory, not recursively.

this find command ahs been tested on hp-ux/linux/aix/solaris.

file -i <textfile>
2009-09-08 01:33:19
User: juvenn
Functions: file

This command gives you the charset of a text file, which would be handy if you have no idea of the encoding.