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.

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.

UpGuard checks and validates configurations for every major OS, network device, and cloud provider.

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 - 241 results
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.

curl -u username:password --silent "https://mail.google.com/mail/feed/atom" | tr -d '\n' | awk -F '<entry>' '{for (i=2; i<=NF; i++) {print $i}}' | sed -n "s/<title>\(.*\)<\/title.*name>\(.*\)<\/name>.*/\2 - \1/p"
2009-09-07 21:56:40
User: postrational
Functions: awk sed tr

Checks the Gmail ATOM feed for your account, parses it and outputs a list of unread messages.

For some reason sed gets stuck on OS X, so here's a Perl version for the Mac:

curl -u username:password --silent "https://mail.google.com/mail/feed/atom" | tr -d '\n' | awk -F '<entry>' '{for (i=2; i<=NF; i++) {print $i}}' | perl -pe 's/^<title>(.*)<\/title>.*<name>(.*)<\/name>.*$/$2 - $1/'

If you want to see the name of the last person, who added a message to the conversation, change the greediness of the operators like this:

curl -u username:password --silent "https://mail.google.com/mail/feed/atom" | tr -d '\n' | awk -F '<entry>' '{for (i=2; i<=NF; i++) {print $i}}' | perl -pe 's/^<title>(.*)<\/title>.*?<name>(.*?)<\/name>.*$/$2 - $1/'
fuser -k `who -u | awk '$6 == "old" { print "/dev/"$2'}`
2009-09-07 03:36:43
User: lbonanomi
Functions: awk fuser
Tags: Linux solaris

Shell timeout variables (TMOUT) can be very liberal about what is classified as 'activity', like having an editor open. This command string will terminate the login shell for an user with more than a day's idle time.

smbpasswd -r <domain-server> -U <user name>
2009-08-12 07:46:48
User: greppo

If you use Linux in a Windows domain and there are N days to expiry, this is how you can change it without resorting to a windows machine.

grep . filename
2009-08-09 05:33:58
Functions: grep
Tags: Linux grep

Remove newlines from output.

One character shorter than awk /./ filename and doesn't use a superfluous cat.

To be fair though, I'm pretty sure fraktil was thinking being able to nuke newlines from any command is much more useful than just from one file.

cat filename | grep .
2009-08-09 01:00:59
User: fraktil
Functions: cat grep
Tags: cat Linux grep

Pipe any output to "grep ." and blank lines will not be printed.

ips(){ for if in ${1:-$(ip link list|grep '^.: '|cut -d\ -f2|cut -d: -f1)};do cur=$(ifconfig $if|grep "inet addr"|sed 's/.*inet addr:\([0-9\.]*\).*/\1/g');printf '%-5s%-15s%-15s\n' $if $cur $(nc -s $cur sine.cluenet.org 128 2>/dev/null||echo $cur);done;}
2009-08-07 10:04:46
User: frozenfire
Functions: cut echo grep ifconfig link sed

Gets the internal and external IP addresses of all your interfaces, or the ones given as arguments

ulimit -s 64
2009-08-06 10:40:25
User: ioggstream
Functions: ulimit
Tags: Linux ulimit

default stack size is 10M. This makes your multithread app filling rapidly your memory.

on my PC I was able to create only 300thread with default stack size.

Lower the default stack size to the one effectively used by your threads, let you create more.

ex. putting 64k I was able to create more than 10.000threads.

Obviously ...your thread shouldn't need more than 64k ram!!!

grep -r . /sys/class/net/eth0/statistics
2009-08-05 08:20:39
User: olorin
Functions: grep
Tags: Linux

Within /proc and /sys there are a lot of subdirectories, which carry pseudofiles with only one value as content. Instead of cat-ing all single files (which takes quite a time) or do a "cat *" (which makes it hard to find the filename/content relation), just grep recursively for . or use "grep . /blabla/*" (star instead of -r flag).

For better readability you might also want to pipe the output to "column -t -s : ".

/sbin/kexec -l /boot/$KERNEL --append="$KERNELPARAMTERS" --initrd=/boot/$INITRD; sync; /sbin/kexec -e
2009-08-03 07:36:49
User: olorin
Tags: Linux boot kexec

If you are doing some tests which require reboots (e. g. startup skripts, kernel module parameters, ...), this is very time intensive, if you have got a hardware with a long pre-boot phase due to hardware checks.

At this time, kexec can help, which only restarts the kernel with all related stuff.

First the kernel to be started is loaded, then kexec -e jumps up to start it.

Is as hard as a reboot -f, but several times faster (e. g. 1 Minute instead of 12 on some servers here).

ifconfig | awk '/ddr:[0-9]/ {sub(/addr:/, ""); print $2}'
2009-07-31 09:30:54
User: danny_b85
Functions: awk ifconfig
Tags: Linux ifconfig

The initial version of this command also outputted extra empty lines, so it went like this:

This happened on Ubuntu, i haven't tested on anything else.

ipconfig getpacket en0 | grep yi| sed s."yiaddr = "."en0: ". ipconfig getpacket en1 | grep yi| sed s."yiaddr = "."en1: ".
ifconfig | awk -F':| +' '/ddr:/{print $4}'
2009-07-25 22:51:08
User: 0x89
Functions: awk ifconfig
Tags: Linux ifconfig

and, a lot uglier, with sed:

ifconfig | sed -n '/inet addr:/s/[^:]\+:\(\S\+\).*/\1/p'


Wanted to be shorter than the perl version. Still think that the perl version is the best..

ifconfig | grep "inet [[:alpha:]]\+" | cut -d: -f2 | cut -d' ' -f2
2009-07-24 13:16:37
User: feraf
Functions: cut grep ifconfig
Tags: Linux ifconfig

Get the IP address of all your network cards.

ifconfig | grep "inet addr" | cut -d: -f2 | cut -d' ' -f1
ifconfig | perl -nle'/dr:(\S+)/ && print $1'
2009-07-23 09:33:31
User: xsawyerx
Functions: ifconfig perl

Fetches the IPs and ONLY the IPs from ifconfig. Simplest, shortest, cleanest.

Perl is too good to be true...

(P.S.: credit should go to Peteris Krumins at catonmat.net)

lomount -diskimage /path/to/your/backup.img -partition 1 /mnt/foo

Instead of calculating the offset and providing an offset option to mount, let lomount do the job for you by just providing the partition number you would like to loop mount.

/originalInstall/gem list | tr -d '(),' | xargs -L 1 sudo ./gemInst.sh
2009-07-09 21:46:06
User: snakerdlk
Functions: sudo tr xargs
Tags: bash Linux



for i in $@; do

if [ "$1" != "$i" ]


echo /newInstall/gem install $1 -v=\"$i\"

/newInstall/gem install $1 -v="$i"

if [ "$?" != "0" ]


echo -e "\n\nGEM INSTALL ERROR: $1\n\n"

echo "$1" > gemInst.err




watch -t -n1 "date +%T|figlet"
2009-06-21 01:02:37
User: dennisw
Functions: watch

This command displays a clock on your terminal which updates the time every second. Press Ctrl-C to exit.

A couple of variants:

A little bit bigger text:

watch -t -n1 "date +%T|figlet -f big"

You can try other figlet fonts, too.

Big sideways characters:

watch -n 1 -t '/usr/games/banner -w 30 $(date +%M:%S)'

This requires a particular version of banner and a 40-line terminal or you can adjust the width ("30" here).