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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.




Commands using date from sorted by
Terminal - Commands using date - 155 results
date --set="$(ssh user@server date)"
2011-08-30 20:03:06
User: splante
Functions: date
Tags: ssh ,NTP ,Date

Shorter, easier to remember version of cmd#7636

NTP is better, but there are situations where it can't be used. In those cases, you can do this to sync the local time to a server.

DATE=$(date +%Y-%m-%d_%H-%M-%S)-$(($(date +%N)/10000000)); HOST=ssh_host; DEST=file_dest; URL=url/screenshot_$DATE.png; import -window root png:- | ssh $HOST "cat > $DEST/screenshot_$DATE.png"; echo $URL | xclip; notify-send -u low "Title" "Message"
2011-08-13 00:40:36
Functions: date echo ssh

Requires you to have password free login to remote host ;)

Requires xclip and notify-send (If you want to put into clipboard and be notified when action is completed).

DATE=$(date +%Y-%m-%d_%H-%M-%S)-$(($(date +%N)/10000000));

HOST="ssh host of your choice";

DEST="destination folder without trailing slash";

URL="URL for file if uploaded to web enabled dir ie.

import -window root png:- | ssh $HOST "cat > $DEST/screenshot_$DATE.png";

echo $URL | xclip; notify-send -u low "Screenshot Taken" "Entire screen.\nCopied to clipboard"

read day month year < <(date +'%d %m %y')
2011-07-30 06:06:29
User: frans
Functions: date read
Tags: bash read

No command substitution but subshell redirection

read day month year <<< $(date +'%d %m %y')
eval $(date +"day=%d; month=%m; year=%y")
2011-07-29 12:47:26
User: xakon
Functions: date eval
Tags: bash eval

It's quite easy to capture the output of a command and assign it in a shell's variable:

day=$(date +%d) month=$(date +%m)

But, what if we want to perform the same task with just one program invocation? Here comes the power of eval! date(1) outputs a string like "day=29; month=07; year=11" (notice the semicolons I added on purpose at date's custom output) which is a legal shell line. This like is then parsed and executed by the shell once again with the help of eval. Just setting 3 variables!

Inspired by LinuxJournal's column "Dave Taylor's Work the Shell".

MAC=$((date +'%Y%m%d%H%M%S%N'; cat /proc/interrupts) | md5sum | sed -r 's/(..)/\1:/g' | cut -d: -f 1-6)
2011-07-14 13:11:50
User: jazznjam
Functions: cat cut date md5sum sed

I liked vaporub's suggestion, here a little simplification of the sed command.

if [ $(date +%u) -lt 6 ];then AT="tomorrow"; else AT="next monday";fi;echo "beep" | at ${AT}
2011-06-01 14:15:11
User: eduo
Functions: at date echo

Line can be modified as needed. This considers weekdays to be Mon-Fri. If run any working day it'll provide a parameters for the next working day for "at".

"beep" provided as a sample command.

This can be modified easily to include wait time. If you need something to run "D" days after today:

# D=4;if [ $(date +%u --date="${D} days") -lt 5 ];then AT="+${D} days";else AT="next monday";fi; echo "beep" | at noon ${AT}

echo $(( $( date +%s ) - $( stat -c %Y * | sort -nr | head -n 1 ) ))
www-browser http://en.wikipedia.org/wiki/$(date +'%b_%d')
2011-05-09 02:42:32
User: benjabean1
Functions: date
Tags: bash

Improved version of command #8425.

This way, the default browser is used, as opposed to Firefox.

firefox http://en.wikipedia.org/wiki/$(date +'%b_%d')
tar jcpf /home/[usuario]/etc-$(hostname)-backup-$(date +%Y%m%d-%H%M%S).tar.bz2 /etc
2011-04-29 22:53:11
User: mack
Functions: date tar

Simple Compressed Backup of the /etc

Linux compatible

date +%Y%m%d%T -s "`ssh user@server 'date "+%Y%m%d %T"'`"
2011-01-11 10:33:32
Functions: date
Tags: ssh ,NTP ,Date

If you are stuck behind a firewall and want to synchronize time with another server but you do not want to port forward NTP (which uses UDP) then this command is handy. It gets the time from a server and sets the local time. It is not that accurate but I can live with a second or so drift.

buf() { cp -v $1 ${1/${1%%.*}/$f-$(date +"%Y%m%d_%H%M%S")};}
buf() { f=${1%%.*};e=${1/$f/};cp -v $1 $f-$(date +"%Y%m%d_%H%M%S")$e;}
2010-12-15 09:50:04
User: unefunge
Functions: cp date

"infix" version in bash (4.x+)

Remove -v to make it silent.

BTW: The OP forgot to use "cat" and "nmap" ;-) I had a good laugh though.

qrurl() { curl "http://chart.apis.google.com/chart?chs=150x150&cht=qr&chld=H%7C0&chl=$1" -o qr.$(date +%Y%m%d%H%M%S).png; }
2010-12-15 04:40:22
User: bartonski
Functions: date

QR codes are those funny square 2d bar codes that everyone seems to be pointing their smart phones at.

Try the following...

qrurl http://xkcd.com

Then open qr.*.png in your favorite image viewer.

Point your the bar code reader on your smart phone at the code, and you'll shortly be reading xkcd on your phone.

URLs are not the only thing that can be encoded by QR codes... short texts (to around 2K) can be encoded this way, although this function doesn't do any URL encoding, so unless you want to do that by hand it won't be useful for that.

buf () {oldname=$1; if [ "$oldname" != "" ]; then datepart=$(date +%Y-%m-%d); firstpart=`echo $oldname | cut -d "." -f 1`; newname=`echo $oldname | sed s/$firstpart/$firstpart.$datepart/`; cp -i ${oldname} ${newname}; fi }
2010-12-14 19:58:34
User: Seebi
Functions: cp cut date sed

This backup function preserve the file suffix allowing zsh suffix aliases and desktop default actions to work with the backup file too.

buf () { cp $1{,$(date +%Y%m%d_%H%M%S)}; }
2010-12-14 14:02:03
User: unefunge
Functions: cp date

1. you don't need to prepend the year with 20 - just use Y instead of y

2. you may want to make your function a bit more secure:

buf () { cp ${1?filename not specified}{,$(date +%Y%m%d_%H%M%S)}; }

buf () { filename=$1; filetime=$(date +%Y%m%d_%H%M%S); cp ${filename} ${filename}_${filetime}; }
2010-12-14 13:19:52
User: dopeman
Functions: cp date
buf myfile.txt

This is useful when you are making small but frequent changes to a file. It keeps things organised and clear for another administrator to see what changed and at what time. An overview of changes can be deduced using a simple:

ls -ltr
read -a A <<<"8 9 5 10 6 0 3 11 7 4";B='.*.**..*....***';for C in $(date +"%H%M"|fold -w1);do echo "${B:${A[C]}:4}";done
for a in $(date +"%H%M"|cut -b1,2,3,4 --output-delimiter=" ");do case "$a" in 0)echo "....";;1)echo "...*";;2)echo "..*.";;3)echo "..**";;4)echo ".*..";;5)echo ".*.*";;6)echo ".**.";;7)echo ".***";;8)echo "*...";;9)echo "*..*";;esac;done
tail -f file | while read line; do echo -n $(date -u -Ins); echo -e "\t$line"; done
2010-11-19 10:01:57
User: hfs
Functions: date echo file read tail
Tags: tail date

This is useful when watching a log file that does not contain timestamps itself.

If the file already has content when starting the command, the first lines will have the "wrong" timestamp when the command was started and not when the lines were originally written.

alias tarred='( ( D=`builtin pwd`; F=$(date +$HOME/`sed "s,[/ ],#,g" <<< ${D/${HOME}/}`#-%F.tgz); tar --ignore-failed-read --transform "s,^${D%/*},`date +${D%/*}.%F`,S" -czPf "$F" "$D" &>/dev/null ) & )'
2010-11-18 06:24:34
User: AskApache
Functions: alias date tar

This is freaking sweet!!! Here is the full alias, (I didn't want to cause display problems on commandlinefu.com's homepage):

alias tarred='( ( D=`builtin pwd`; F=$(date +$HOME/`sed "s,[/ ],#,g" <<< ${D/${HOME}/}`#-%F.tgz); S=$SECONDS; tar --ignore-failed-read --transform "s,^${D%/*},`date +${D%/*}.%F`,S" -czPf "$"F "$D" && logger -s "Tarred $D to $F in $(($SECONDS-$S)) seconds" ) & )'

Creates a .tgz archive of whatever directory it is run from, in the background, detached from current shell so if you logout it will still complete. Also, you can run this as many times as you want, if the archive .tgz already exists, it just moves it to a numbered backup '--backup=numbered'. The coolest part of this is the transformation performed by tar and sed so that the archive file names are automatically created, and when you extract the archive file it is completely safe thanks to the transform command.

If you archive lets say /home/tombdigger/new-stuff-to-backup/ it will create the archive /home/#home#tombdigger#new-stuff-to-backup#-2010-11-18.tgz Then when you extract it, like tar -xvzf #home#tombdigger#new-stuff-to-backup#-2010-11-18.tgz instead of overwriting an existing /home/tombdigger/new-stuff-to-backup/ directory, it will extract to /home/tombdigger/new-stuff-to-backup.2010-11-18/

Basically, the tar archive filename is the PWD with all '/' replaced with '#', and the date is appended to the name so that multiple archives are easily managed. This example saves all archives to your $HOME/archive-name.tgz, but I have a $BKDIR variable with my backup location for each shell user, so I just replaced HOME with BKDIR in the alias.

So when I ran this in /opt/askapache/SOURCE/lockfile-progs-0.1.11/ the archive was created at /askapache-bk/#opt#askapache#SOURCE#lockfile-progs-0.1.11#-2010-11-18.tgz

Upon completion, uses the universal logger tool to output its completion to syslog and stderr (printed to your terminal), just remove that part if you don't want it, or just remove the '-s ' option from logger to keep the logs only in syslog and not on your terminal.

Here's how my syslog server recorded this..

2010-11-18T00:44:13-05:00 gravedigger.askapache.com ( [user] [notice] (logger:) Tarred /opt/askapache/SOURCE/lockfile-progs-0.1.11 to /askapache-bk/tarred/#opt#SOURCE#lockfile-progs-0.1.11#-2010-11-18.tgz in 4 seconds


Really this is very robust and foolproof, the only issues I ever have with it (I've been using this for years on my web servers) is if you run it in a directory and then a file changes in that directory, you get a warning message and your archive might have a problem for the changed file. This happens when running this in a logs directory, a temp dir, etc.. That's the only issue I've ever had, really nothing more than a heads up.


This is a simple alias, and very useful as it works on basically every linux box with semi-current tar and GNU coreutils, bash, and sed.. But if you want to customize it or pass parameters (like a dir to backup instead of pwd), check out this function I use.. this is what I created the alias from BTW, replacing my aa_status function with logger, and adding $SECONDS runtime instead of using tar's --totals

function tarred ()


local GZIP='--fast' PWD=${1:-`pwd`} F=$(date +${BKDIR}/%m-%d-%g-%H%M-`sed -u 's/[\/\ ]/#/g'

[[ ! -r "$PWD" ]] && echo "Bad permissions for $PWD" 1>&2 && return 2;

( ( tar --totals --ignore-failed-read --transform "s@^${PWD%/*}@`date +${PWD%/*}.%m-%d-%g`@S" -czPf $F $PWD && aa_status "Completed Tarp of $PWD to $F" ) & )


#From my .bash_profile http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

tar cfz backup-$(date --iso).tar.gz somedirs
date +"%V"
2010-11-17 14:59:31
User: SuperFly
Functions: date

Not as cool as the python example, but it still works.

wget -O xkcd_$(date +%y-%m-%d).png `lynx --dump http://xkcd.com/|grep png`; eog xkcd_$(date +%y-%m-%d).png