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.

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



Psst. Open beta.

Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:

  • » The open beta is running a copy of the database that will not carry over to the final version. Don't post anything you don't mind losing.
  • » If you wish to use your user account, you will probably need to reset your password.
Your feedback is appreciated via the form on the beta page. Thanks! -Jon & CLFU Team

Commands using tail from sorted by
Terminal - Commands using tail - 244 results
url=http://www.youtube.com/watch?v=V5bYDhZBFLA; youtube-dl -b $url; mplayer $(ls ${url##*=}*| tail -n1) -ss 00:57 -endpos 10 -vo gif89a:fps=5:output=output.gif -vf scale=400:300 -nosound
2010-07-18 02:11:39
User: zed
Functions: ls tail

requires "youtube-dl" -- sure you can do this with wget and some more obscurity but why waste your time when this great tool is available?

the guts consist of mplayer converting a video to a gif -- study this command and read the man page for more information

mplayer video.flv -ss 00:23 -endpos 6 -vo gif89a:fps=5:output=output.gif -vf scale=400:300 -nosound

generates a 6 second gif starting at 23 seconds of play time at 5 fps and a scale of 400x300

start time (-ss)/end time (-endpos) formats: 00:00:00.000

end time should be relative to start time, not absolute. i.e. -endpos 5 == seconds after 0:42 = 0:47 end point

play with fps and scale for lower gif sizes

the subshell is a solution for the -b flag on youtube-dl which downloads the best quality video, sometimes, which can be various video formats $(ls ${url##*=}*| tail -n1)

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.

tail -n +4 | head -n 1
head -n X | tail -n 1
2010-07-08 22:06:39
User: infinull
Functions: head tail

using tail first won't do it because tail counts from the bottom of the file. You could do it this way but I don't suggest it

tail -n 4 | head -n 1
2010-07-08 19:50:06
User: puddy
Functions: head tail

tail -n X | head -n 1

prints a specific line, where X is the line number

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.

tune2fs -l $(df -P / | tail -n1 | cut -d' ' -f1 ) | grep 'Filesystem created:'
diff <(tail -10 file1) <(tail -10 file2)
tail -fs 1 somefile
2010-05-18 23:42:35
User: ppaschka
Functions: tail

The -s option allows you to specify the update interval

tail -n2000 /var/www/domains/*/*/logs/access_log | awk '{print $1}' | sort | uniq -c | sort -n | awk '{ if ($1 > 20)print $1,$2}'
mplayer http://minnesota.publicradio.org/tools/play/streams/the_current.pls < /dev/null | grep --line-buffered "StreamTitle='.*S" -o | grep --line-buffered "'.*'" -o > mus & tail -n0 -f mus | while read line; do notify-send "Music Change" "$line";done
2010-05-09 17:51:40
User: spiffwalker
Functions: grep read tail

Plays the mp3 stream of The Current as a background job. When you are done run:

fg %1

then to exit

Quite possible with Growl for mac I'd guess, although have not tried.

Libnotify needed for notification, stream will still work otherwise

tail -f error_log | nc -l 1234
2010-05-07 18:14:04
User: zlemini
Functions: tail

Netcat is used to serve a log-file over a network on port 1234.

Point a browser to the specified server/port combo to view log-file updates in real-time.

/etc/init.d/cron restart && tail -100 /var/log/syslog
2010-05-05 09:56:30
User: root
Functions: tail

Debian-specific but very useful as cron files are prone to very subtle gotchas

shopt -s extglob; for f in *.ttf *.TTF; do g=$(showttf "$f" 2>/dev/null | grep -A1 "language=0.*FullName" | tail -1 | rev | cut -f1 | rev); g=${g##+( )}; mv -i "$f" "$g".ttf; done

Just a quick hack to give reasonable filenames to TrueType and OpenType fonts.

I'd accumulated a big bunch of bizarrely and inconsistently named font files in my ~/.fonts directory. I wanted to copy some, but not all, of them over to my new machine, but I had no idea what many of them were. This script renames .ttf files based on the name embedded inside the font. It will also work for .otf files, but make sure you change the mv part so it gives them the proper extension.

REQUIREMENTS: Bash (for extended pattern globbing), showttf (Debian has it in the fontforge-extras package), GNU grep (for context), and rev (because it's hilarious).

BUGS: Well, like I said, this is a quick hack. It grew piece by piece on the command line. I only needed to do this once and spent hardly any time on it, so it's a bit goofy. For example, I find 'rev | cut -f1 | rev' pleasantly amusing --- it seems so clearly wrong, and yet it works to print the last argument. I think flexibility in expressiveness like this is part of the beauty of Unix shell scripting. One-off tasks can be be written quickly, built-up as a person is "thinking aloud" at the command line. That's why Unix is such a huge boost to productivity: it allows each person to think their own way instead of enforcing some "right way".

On a tangent: One of the things I wish commandlinefu would show is the command line HISTORY of the person as they developed the script. I think it's that conversation between programmer and computer, as the pipeline is built piece-by-piece, that is the more valuable lesson than any canned script.

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

tail -f access.log | pv -l -i10 -r >/dev/null
2010-04-29 21:02:01
User: dooblem
Functions: tail
Tags: tail pv

Displays the realtime line output rate of a logfile.

-l tels pv to count lines

-i to refresh every 10 seconds

-l option is not in old versions of pv. If the remote system has an old pv version:

ssh tail -f /var/log/apache2/access.log | pv -l -i10 -r >/dev/null

tail -f access_log | cut -c2-21 | uniq -c
2010-04-29 11:16:54
User: buzzy
Functions: cut tail uniq
Tags: uniq tail cut

Change the cut range for hits per 10 sec, minute and so on... Grep can be used to filter on url or source IP.

for i in emerg alert crit error warn ; do awk '$6 ~ /^\['$i'/ {print substr($0, index($0,$6)) }' error_log | sort | uniq -c | sort -n | tail -1; done
2010-04-15 21:47:18
User: zlemini
Functions: awk sort tail uniq

This searches the Apache error_log for each of the 5 most significant Apache error levels, if any are found the date is then cut from the output in order to sort then print the most common occurrence of each error.

tail /var/log/emerge.log | awk -F: '{print strftime("%Y%m%d %X %Z", $1),$2}'
date +%A | tail -2c
2010-04-08 15:14:06
User: inof
Functions: date tail

Several people have submitted commands to do this, but I think this is the simplest solution. It also happens to be the most portable one: It should work with any sh or csh derived shell under any UNIX-like OS.

Oh by the way, with my German locale ($LC_TIME set appropriately) it prints "g" most of the time, and sometimes (on Wednesdays) it prints "h". It never prints "y".

open-command $(ls -rt *.type | tail -n 1)
2010-04-04 20:43:38
User: RBerenguel
Functions: ls tail

Change open-command and type to suit your needs. One example would be to open the last .jpg file with Eye Of Gnome:

eog $(ls -rt *.jpg | tail -n 1)

curl -s -L --head -w "%{http_code}\n" URL | tail -n1
TR=`free|grep Mem:|awk '{print $2}'`;ps axo rss,comm,pid|awk -v tr=$TR '{proc_list[$2]+=$1;} END {for (proc in proc_list) {proc_pct=(proc_list[proc]/tr)*100; printf("%d\t%-16s\t%0.2f%\n",proc_list[proc],proc,proc_pct);}}'|sort -n |tail -n 10
2010-03-27 01:34:50
User: d34dh0r53
Functions: awk grep sort tail

Prints the top 10 memory consuming processes (with children and instances aggregated) sorted by total RSS and calculates the percentage of total RAM each uses. Please note that since RSS can include shared libraries it is possible for the percentages to add up to more that the total amount of RAM, but this still gives you a pretty good idea. Also note that this does not work with the mawk version of awk, but it works fine with GNU Awk which is on most Linux systems. It also does not work on OS X.

find * \( -name "*.[hc]pp" -or -name "*.py" -or -name "*.i" \) -print0 | xargs -0 wc -l | tail -n 1
2010-03-25 18:58:29
User: neologism
Functions: find tail wc xargs
Tags: find xargs wc

Finds all C++, Python, SWIG files in your present directory (uses "*" rather than "." to exclude invisibles) and counts how many lines are in them. Returns only the last line (the total).

ps axo rss,comm,pid | awk '{ proc_list[$2] += $1; } END { for (proc in proc_list) { printf("%d\t%s\n", proc_list[proc],proc); }}' | sort -n | tail -n 10