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 using date from sorted by
Terminal - Commands using date - 163 results
while true; do (echo -n $(date +"%F %T"):\ ; xwininfo -id $(xprop -root|grep "ACTIVE_WINDOW("|cut -d\ -f 5) | grep "Window id" | cut -d\" -f 2 ) >> logfile; sleep 60; done
2015-09-23 23:00:14
User: BeniBela
Functions: cut date echo grep sleep

This logs the titles of the active windows, thus you can monitor what you have done during which times. (it is not hard to also log the executable name, but then it is gets too long)

[ $(date +"%H") -lt 7 ] && echo you should probably be sleeping...
sed -i.$(date +%F@%T) 's/^LogLevel warn/LogLevel debug/g' httpd.conf
2015-07-22 14:47:26
User: zlemini
Functions: date sed

httpd.conf httpd.conf.2015-07-22@14:43:20

if [[ $(expr $(date +%s) - $(stat -c %X /var/lib/apt/periodic/update-success-stamp)) -gt 86400 ]]; then sudo apt-get update fi
2015-05-12 14:45:11
User: gargolito
Functions: date expr stat sudo

I have this in my .bash_aliases and call it before running apt-get install or apt-get upgrade


alias apt-install='apt-update; apt-get install'

alias apt-upgrade='apt-update; apt-get upgrade'

function apt-update () {

if [[ $(expr $(date +%s) - $(stat -c %X /var/lib/apt/periodic/update-success-stamp)) -gt 86400 ]]; then

sudo apt-get update


echo apt is up to date



while [ $(( $(date +%s) - $(stat -c %Y FILENAME) )) -lt 10 ]; do sleep 1; done; echo DONE
2015-05-09 12:30:13
User: flatcap
Functions: date echo sleep stat

This loop will finish if a file hasn't changed in the last 10 seconds.


It checks the file's modification timestamp against the clock.

If 10 seconds have elapsed without any change to the file, then the loop ends.


This script will give a false positive if there's a 10 second delay between updates,

e.g. due to network congestion


How does it work?

'date +%s' gives the current time in seconds

'stat -c %Y' gives the file's last modification time in seconds

'$(( ))' is bash's way of doing maths

'[ X -lt 10 ]' tests the result is Less Than 10

otherwise sleep for 1 second and repeat


Note: Clever as this script is, inotify is smarter.

echo $(date +%m) past $(date +%H) | espeak
2015-05-09 12:24:13
User: hal8
Functions: date echo

s/espeak/say/ on a mac

clear; while sleep 1; do d=$(date +"%H:%M:%S"); e=$(echo "toilet -t -f mono12 $d");tput setaf 1 cup 0; eval $e; tput setaf 4 cup 8; eval "$e -F flop";tput cup 0; done
ssh user@server sudo date -s @`( date -u +"%s" )`
crontest () { date +'%M %k %d %m *' |awk 'BEGIN {ORS="\t"} {print $1+2,$2,$3,$4,$5,$6}'; echo $1;}
2015-03-12 19:56:56
User: CoolHand
Functions: awk date echo

usage = crontest "/path/to/bin"

This version of this function will echo back the entire command so it can be copied/pasted to crontab. Should be able to be automagically appended to crontab with a bit more work. Tested on bash and zsh on linux,freebsd,aix

for file in $(find /var/backup -name "backup*" -type f |sort -r | tail -n +10); do rm -f $file; done ; tar czf /var/backup/backup-system-$(date "+\%Y\%m\%d\%H\%M-\%N").tgz --exclude /home/dummy /etc /home /opt 2>&- && echo "system backup ok"
2014-09-24 14:04:11
User: akiuni
Functions: date echo file find rm sort tail tar
Tags: backup Linux cron

this command can be added to crontab so as to execute a nightly backup of directories and store only the 10 last backup files.

date -r 1390196676
function findOlderThan () { find . -mmin -$((($(date "+%s") - $(stat -c %Y $1))/60)) -type f ; }
2014-08-29 17:52:34
User: RobertDeRose
Functions: date find stat
Tags: find date stat

This function will find the modification time in unix_time of the given file, then calculate the number of minutes from now to then and then find all files modified in that range.

YEAR=2015; date -d${YEAR}0801-$(date -d${YEAR}0801+2days +%u)days +%b\ %e
2014-08-17 11:06:25
User: andreasS
Functions: date
Tags: date

Calculate Sysadmin day of any given year using 2 `date`. Code based on http://stackoverflow.com/a/5656859/196133

[ `curl 'http://crl.godaddy.com/gds5-16.crl' 2>/dev/null | openssl crl -inform DER -noout -nextupdate | awk -F= '{print $2}' | xargs -I{} date -d {} +%s` -gt `date -d '8 hours' +%s` ] && echo "OK" || echo "Expires soon"
2014-08-07 17:18:38
User: hufman
Functions: awk date echo xargs
Tags: openssl

Downloads a CRL file, determines the expiration time, and checks when it will expire

echo {-1..-5}days | xargs -n1 date +"%Y-%m-%d" -d
date -d @1268727836
2014-05-19 09:53:03
Functions: date

The easiest way to convert epoch date to human readable format.

$ date --date='@1268727836'
date -u `ssh user@remotehost date -u '+%m%d%H%M%Y.%S'`
2014-02-10 03:11:14
User: scruss
Functions: date

Useful if localhost is a small machine running BusyBox, which uses a slightly unusual format to set the date. Remotehost can be pretty much any Linux machine, including one running BusyBox. Uses UTC for portability.

(date "+%d-%m-%Y %H:%M:%S";curl -s --interface lo:1 ifconfig.me| xargs -t geoiplookup 2>&1)|sed -e 's/geoiplookup/IP:/g' -e 's/GeoIP Country Edition/Country/g'|tr -s "\n" " "|sed 'a\ '
2013-10-07 15:28:55
User: guerito
Functions: date sed tr xargs

My first command :) I made this command to log public addresses of a virtual interface who connects random VPN servers around the world.

alias timer='export ts=$(date +%s);p='\''$(date -u -d @"$(($(date +%s)-$ts))" +"%H.%M.%S")'\'';watch -n 1 -t banner $p;eval "echo $p"'
2013-08-24 16:18:45
User: ichbins
Functions: alias banner date eval watch
Tags: timer banner

Starts and shows a timer. banner command is a part of the sysvbanner package. Instead of the banner an echo or figlet commands could be used. Stop the timer with Ctrl-C and elapsed time will be shown as the result.

curl -sL http://www.dell.com/support/troubleshooting/us/en/555/Servicetag/$(dmidecode -s system-serial-number) | html2text -style pretty | awk -F\. '/with an end date of/ { print $1 "."}'
2013-07-30 14:46:12
User: mhollick
Functions: awk date

pretty much the same.

I use awk rather than grep and perl.

It looks like the URL has been updated.

The service tag can also be retrieved via snmp - potential for a for loop over a list of servers. I might have a look into doing an example.

date --set="$(ssh user@server 'date -u')"
2013-06-03 06:43:49
Functions: date
Tags: ssh ,NTP ,Date

using -u is better for standardizing date output and timezones, for servers in different timezones.

date -d @1234567890
date '+%y%m%d-%H%M%S'
while (true); do date --utc; done | uniq -c