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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 sleep from sorted by
Terminal - Commands using sleep - 240 results
while :; do ping -W1 -c1 -n > /dev/null || tput bel > /dev/console; sleep 1; done
2010-09-24 06:34:12
User: hackerb9
Functions: ping sleep tput

This is like ping -a, but it does the opposite. It alerts you if the network is down, not up. Note that the beep will be from the speaker on the server, not from your terminal.

Once a second, this script checks if the Internet is accessible and beeps if it is not. I define the Net as being "UP", if I can ping Google's public DNS server (, but of course you could pick a different static IP address. I redirect the beep to /dev/console so that I can run this in the background from /etc/rc.local. Of course, doing that requires that the script is run by a UID or GID that has write permissions to /dev/console (usually only root).

Question: I am not sure if the -W1 flag works under BSD. I have only tested this under GNU/Linux using ping from iputils. If anybody knows how portable -W is, please post a comment.

sleep 4; F="$(tempfile -s '.xwd')"; xwd > "$F" ; gimp "$F"
for x in $(eselect bashcomp list | sed -e 's/ //g' | cut -d']' -f2 | sed -e 's/\*//');do eselect bashcomp enable $x --global;sleep 0.5s;done
2010-09-21 00:17:26
User: chronos
Functions: cut enable sed sleep

enable each bash completion that you have installed at your system, that's very nice ;)

sleep 4; xwd > /tmp/_.xwd ; gimp /tmp/_.xwd
sleep 4; xwd >foo.xwd; mv foo.xwd "$(dd skip=100 if=foo.xwd bs=1 count=256 2>/dev/null | egrep -ao '^[[:print:]]+' | tr / :).xwd"
2010-09-19 08:03:02
User: hackerb9
Functions: mv sleep

In general, this is actually not better than the "scrot -d4" command I'm listing it as an alternative to, so please don't vote it down for that. I'm adding this command because xwd (X window dumper) comes with X11, so it is already installed on your machine, whereas scrot probably is not. I've found xwd handy on boxen that I don't want to (or am not allowed to) install packages on.

NOTE: The dd junk for renaming the file is completely optional. I just did that for fun and because it's interesting that xwd embeds the window title in its metadata. I probably should have just parsed the output from file(1) instead of cutting it out with dd(1), but this was more fun and less error prone.

NOTE2: Many programs don't know what to do with an xwd format image file. You can convert it to something normal using NetPBM's xwdtopnm(1) or ImageMagick's convert(1). For example, this would work: "xwd | convert fd:0 foo.jpg". Of course, if you have ImageMagick already installed, you'd probably use import(1) instead of xwd.

NOTE3: Xwd files can be viewed using the X Window UnDumper: "xwud <foo.xwd". ImageMagick and The GIMP can also read .xwd files. Strangely, eog(1) cannot.

NOTE4: The sleep is not strictly necessary, I put it in there so that one has time to raise the window above any others before clicking on it.

while true; do du -s <file_or_directory>; sleep <time_interval>; done
2010-08-24 19:55:13
User: potatoface
Functions: du sleep

very handy if you copy or download a/some file(s) and want to know how big it is at the moment

while (true); do clear; uname -n; echo ""; df -h /; echo ""; tail -5 /var/log/auth.log; echo ""; vmstat 1 5; sleep 15; done
2010-08-23 04:37:58
User: roknir
Functions: df echo sleep tail uname vmstat

You can use this one-liner for a quick and dirty (more customizable) alternative to the watch command. The keys to making this work: everything exists in an infinite loop; the loop starts with a clear; the loop ends with a sleep. Enter whatever you'd like to keep an eye on in the middle.

chvt 7 ; sleep 2 ; DISPLAY=:0.0 import -window root screenshot.png
2010-08-20 17:28:49
User: camocrazed
Functions: chvt sleep

when using Gnome or KDE, you will have a hard time getting a screenshot of something like a login screen, or any other screen that occurs before the desktop environment is up and monitoring the printscreen key. (this probably applies for other DEs as well, but I haven't used them)

What this command is meant to do is take a screenshot of an X window using a command you can run from your virtual terminals (actual text terminals, not just an emulator) To do this:

Press CTRL+ALT+F1 to go to a virtual (text) terminal once your login window comes up

Login to the virtual terminal and enter the command (you'll have to type it in)

You should now have a file called screenshot.png in your home directory with your screenshot in it.

For those of you who are new to the virtual terminal thing, you can use CTRL+ALT+F7 to get back to your regular GUI

From http://www.gnome.org

maxplayer (){ while :; do xte 'mousermove -4 20'; sleep 1s; xte 'mousermove 4 -20'; sleep 2m; done& mplayer -fs "$1"; fg; }
( ( while [ 2000 -ge "$(free -m | awk '/buffers.cache:/ {print $4}')" ] || [ $(echo "$(uptime | awk '{print $10}' | sed -e 's/,$//' -e 's/,/./') >= $(grep -c ^processor /proc/cpuinfo)" | bc) -eq 1 ]; do sleep 10; done; my-command > output.txt ) & )
2010-07-13 09:12:11
User: michelsberg
Functions: echo sleep

[ 2000 -ge "$(free -m | awk '/buffers.cache:/ {print $4}')" ] returns true if less than 2000 MB of RAM are available, so adjust this number to your needs.

[ $(echo "$(uptime | awk '{print $10}' | sed -e 's/,$//' -e 's/,/./') >= $(grep -c ^processor /proc/cpuinfo)" | bc) -eq 1 ] returns true if the current machine load is at least equal to the number of CPUs.

If either of the tests returns true we wait 10 seconds and check again. If both tests return false, i.e. 2GB are available and machine load falls below number of CPUs, we start our command and save it's output in a text file.

The ( ( ... ) & ) construct lets the command run in background even if we log out. See http://www.commandlinefu.com/commands/view/3115/ .

while (( 1==1 )); do du -c . >> output.log; sleep 2; done; tail -f output.log
2010-07-12 17:23:45
User: aceiro
Functions: du sleep tail

this command shows the space used in postgres directory.

c=0; n=8; while true; do r=`echo $RANDOM%5 |bc`; echo "sleep $r"; sleep $r& 2>&1 >/dev/null && ((c++)); [ `echo "$c%$n" | bc` -eq 0 ] && echo "$c waiting" && wait; done
2010-07-08 13:56:28
User: cp
Functions: echo sleep

the block of the loop is useful whenever you have huge junks of similar jobs, e.g., convert high res images to thumbnails, and make usage out of all the SMP power on your compute box without flooding the system.

note: c is used as counter and the random sleep

r=`echo $RANDOM%5 |bc`; echo "sleep $r"; sleep $r

is just used as a dummy command.

sleep 6s && notify-send -t 10000 -u critical "remember to think" &
2010-07-01 02:17:24
User: zed
Functions: sleep

This will be seen through your system's visual notification system, notify-osd, notification-daemon, etc.


sleep accepts s,m,h,d and floats (date; sleep .25m; date)


notify-send (-t is in milliseconds && -u low / normal / critical)

man notify-send for more information


notification-daemon can use b/i/u/a HTML

function countdown { case "$1" in -s) shift;; *) set $(($1 * 60));; esac; local S=" "; for i in $(seq "$1" -1 1); do echo -ne "$S\r $i\r"; sleep 1; done; echo -e "$S\rBOOM!"; }
2010-06-30 12:20:01
User: kniht
Functions: echo seq set sleep
Tags: timer counter

The biggest advantage over atoponce's nifty original is not killing the scrollback. Written assuming bash, but shouldn't be terribly difficult to port to other shells. S should be multiple spaces, but I can't get commandlinefu to save/show them properly, any help?

sleep 8h && while [ 1 ] ; do date "+Good Morning. It is time to wake up. The time is %I %M %p" | espeak -v english -p 0 -s 150 -a 100 ; sleep 1m; done
2010-06-23 17:34:54
User: copremesis
Functions: date sleep

This ran on a ubuntu box using espeak for speaking text with the bash shell. On a mac you should use 'say'. Also you can change your alarm interval and your snooze interval which are currently 8 hours and 1 minute. I would run this via cron yet it's easier to disable if you run it as a command like this :P

i=$((15*60)); while [ $i -gt 0 ]; do clear; echo $i | figlet; sleep 1; i=$(($i-1)); done;
2010-06-22 17:49:36
User: atoponce
Functions: echo sleep
Tags: figlet timer

Requires figlet. Other than that, this should be portable enough across all the Bourne-compatible shells (sh, bash, ksh, zsh, etc).

Produces a massive number using figlet that counts down the number of seconds for any given minute interval. For example, here's a 4-minute timer:

i=$((4*60)); while [ $i -gt 0 ]; do clear; echo $i | figlet; sleep 1; i=$(($i-1)); done;

And a 1-minute timer:

i=$((1*60)); while [ $i -gt 0 ]; do clear; echo $i | figlet; sleep 1; i=$(($i-1)); done;
MIN=1 && for i in $(seq $(($MIN*60)) -1 1); do echo -n "$i, "; sleep 1; done; echo -e "\n\nBOOOM! Time to start."
2010-06-20 15:19:12
User: atoponce
Functions: echo seq sleep
Tags: timer counter

Simple countdown clock that should be quite portable across any Bourne-compatible shell. I used to teach for a living, and I would run this code when it was time for a break. Usually, I would set "MIN" to 15 for a 15-minute break. The computer would be connected to a projector, so this would be projected on screen, front and center, for all to see.

while true;do clear;echo -n Current\ `grep voltage /proc/acpi/battery/BAT0/state | awk '{print $2" "$3" "$4}'`;for i in `seq 1 5`;do sleep 1;echo -n .;done;done
IFS=`echo -en "\n\b"`; for i in $(curl http://feeds.digg.com/digg/container/technology/popular.rss | grep '<title>' | sed -e 's#<[^>]*>##g' | tail -n10); do echo $i; echo $i | sed 's/^/Did you hear about /g' | say; sleep 30; done
2010-06-07 22:16:19
User: echosedawk
Functions: echo grep sed sleep tail
Tags: bash sed curl osx

Instead of having someone else read you the Digg headlines, Have OSX do it. Requires Curl+Sed+Say. This could probably be easily modified to use espeak for Linux.

$COMMAND 2>&1 >/dev/null & WPID=$!; sleep $TIMEOUT && kill $! & KPID=$!; wait $WPID
2010-05-26 11:12:26
User: keymon
Functions: kill sleep wait

I like much more the perl solution, but without using perl. It launches a backgroup process that will kill the command if it lasts too much.

A bigger function:

check_with_timeout() {

[ "$DEBUG" ] && set -x




# Launch command in backgroup

[ ! "$DEBUG" ] && exec 6>&2 # Link file descriptor #6 with stderr.

[ ! "$DEBUG" ] && exec 2> /dev/null # Send stderr to null (avoid the Terminated messages)

$COMMAND 2>&1 >/dev/null &


[ "$DEBUG" ] && echo "Background command pid $COMMAND_PID, parent pid $$"

# Timer that will kill the command if timesout

sleep $TIMEOUT && ps -p $COMMAND_PID -o pid,ppid |grep $$ | awk '{print $1}' | xargs kill &


[ "$DEBUG" ] && echo "Killer command pid $KILLER_PID, parent pid $$"



# Kill the killer timer

[ "$DEBUG" ] && ps -e -o pid,ppid |grep $KILLER_PID | awk '{print $1}' | xargs echo "Killing processes: "

ps -e -o pid,ppid |grep -v PID | grep $KILLER_PID | awk '{print $1}' | xargs kill


sleep 1

[ ! "$DEBUG" ] && exec 2>&6 6>&- # Restore stderr and close file descriptor #6.

return $RET


tail -n0 -f access.log>/tmp/tmp.log & sleep 10; kill $! ; wc -l /tmp/tmp.log
2010-04-29 21:23:46
User: dooblem
Functions: kill sleep tail wc
Tags: tail kill wc sleep

Another way of counting the line output of tail over 10s not requiring pv.

Cut to have the average per second rate :

tail -n0 -f access.log>/tmp/tmp.log & sleep 10; kill $! ; wc -l /tmp/tmp.log | cut -c-2

You can also enclose it in a loop and send stderr to /dev/null :

while true; do tail -n0 -f access.log>/tmp/tmp.log & sleep 2; kill $! ; wc -l /tmp/tmp.log | cut -c-2; done 2>/dev/null

very_long_command& sleep 10; kill $!
2010-04-29 20:43:13
User: dooblem
Functions: kill sleep

or "Execute a command with a timeout"

Run a command in background, sleep 10 seconds, kill it.

! is the process id of the most recently executed background command.

You can test it with:

find /& sleep10; kill $!

mv ubuntu-10.04-rc-desktop-amd64.iso ubuntu-10.04-desktop-amd64.iso; i=http://releases.ubuntu.com/10.04/ubuntu-10.04-desktop-amd64.iso.zsync; while true; do if wget $i; then zsync $i; date; break; else sleep 30; fi; done
2010-04-29 15:49:43
Functions: mv sleep wget

Need to have rc iso pre-downloaded before running command.

while true; do if wget http://releases.ubuntu.com/10.04/ubuntu-10.04-desktop-i386.iso.torrent; then ktorrent --silent ubuntu-10.04-desktop-i386.iso.torrent ; date; break; else sleep 5m; fi; done
2010-04-29 13:22:54
User: ppaschka
Functions: sleep wget

Tested with 9.10 release. Choose whatever torrent client you prefer.

diff <(lsof -p 1234) <(sleep 10; lsof -p 1234)
2010-03-15 22:55:32
User: zlemini
Functions: diff sleep

This command takes a snapshot of the open files for a PID 1234 then waits 10 seconds and takes another snapshot of the same PID, it then displays the difference between each snapshot to give you an insight into what the application is doing.