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 tail from sorted by
Terminal - Commands using tail - 239 results
tail -f /var/log/squid/access.loc | ccze -CA
tail -n0 -f /var/log/messages | while read line; do notify-send "System Message" "$line"; done
2011-07-11 22:33:24
User: hukketto
Functions: read tail
Tags: notify-send

It willl popup a message for each new entry in /var/log/messages

found on the notify-send howto page on ubuntuforums.org.

Posted here only because it is one of the favourites of mine.

tail -f /var/log/squid/access.log | perl -p -e 's/^([0-9]*)/"[".localtime($1)."]"/e'
tail -f /var/log/logfile|perl -e 'while (<>) {$l++;if (time > $e) {$e=time;print "$l\n";$l=0}}'
2011-06-21 10:28:26
User: madsen
Functions: perl tail time
Tags: perl tail

Using tail to follow and standard perl to count and print the lps when lines are written to the logfile.

head -n1 sample.txt | tail -n1
2011-06-14 17:45:04
User: gtcom
Functions: head tail
Tags: tail HEAD

You can actually do the same thing with a combination of head and tail. For example, in a file of four lines, if you just want the middle two lines:

head -n3 sample.txt | tail -n2

Line 1 --\

Line 2 } These three lines are selected by head -n3,

Line 3 --/ this feeds the following filtered list to tail:

Line 4

Line 1

Line 2 \___ These two lines are filtered by tail -n2,

Line 3 / This results in:

Line 2

Line 3

being printed to screen (or wherever you redirect it).

history | tail -(n+1) | head -(n) | sed 's/^[0-9 ]\{7\}//' >> ~/script.sh
2011-06-08 13:40:58
Functions: head sed tail

Uses history to get the last n+1 commands (since this command will appear as the most recent), then strips out the line number and this command using sed, and appends the commands to a file.

tail /var/log/auth.log -n 100
ls -atr /home/reports/*.csv -o --time-sty=+%s | tail -1 | awk '{print systime()-$5}'
FILE=`ls -ltr /var/lib/pgsql/backups/daily/ | tail -n1 | awk '{print $NF}'`; TIME=`stat -c %Y /var/lib/pgsql/backups/daily/$FILE`; NOW=`date +%s`; echo $((NOW-TIME))
find . -printf '%d\n' | sort -n | tail -1
find /var/log -iregex '.*[^\.][^0-9]+$' -not -iregex '.*gz$' 2> /dev/null | xargs tail -n0 -f | ccze -A
tail -f /var/log/messages | espeak
2011-04-08 10:24:49
User: dmytrish
Functions: tail

you can listen to your computer, but don't be carried away

tail -f somefile |tee >(grep --line-buffered '1' > one.txt) |tee >(grep --line-buffered '2' > two.txt)
2011-04-03 10:05:28
User: binaryten
Functions: grep tail tee

when using named pipes only one reader is given the output by default. Also, most commands piped to by grep use a buffer which save output until tail -f finishes, which is not convenient. Here, using a combination of tee, sub-processes and the --line-buffered switch in grep we can workaround the problem.

history | awk '{print $2}' | awk 'BEGIN {FS="|"}{print $1}' | sort | uniq -c | sort -n | tail | sort -nr
curl http://www.discogs.com/search?q=724349691704 2> /dev/null | grep \/release\/ | head -2 | tail -1 | sed -e 's/^<div>.*>\(.*\)<\/a><\/div>/\1/'
wget http://www.discogs.com/search?q=724349691704 -O foobar &> /dev/null ; grep \/release\/ foobar | head -2 | tail -1 | sed -e 's/^<div>.*>\(.*\)<\/a><\/div>/\1/' ; rm foobar
2011-01-30 23:34:54
User: TetsuyO
Functions: grep head rm sed tail wget

Substitute that 724349691704 with an UPC of a CD you have at hand, and (hopefully) this oneliner should return the $Artist - $Title, querying discogs.com.

Yes, I know, all that head/tail/grep crap can be improved with a single sed command, feel free to send "patches" :D


curl -s http://www.last.fm/user/$LASTFMUSER | grep -A 1 subjectCell | sed -e 's#<[^>]*>##g' | head -n2 | tail -n1 | sed 's/^[[:space:]]*//g'
/usr/bin/lynx -dump http://www.netins.net/dialup/tools/my_ip.shtml | grep -A2 "Your current IP Address is:" | tail -n1 | tr -d ' '|sed '/^$/d'| sed 's/^ *//g'
ping -q -c 1 www.google.com|tail -1|cut -d/ -f5
alias -g R=' &; jobs | tail -1 | read A0 A1 A2 cmd; echo "running $cmd"; fg "$cmd"; zenity --info --text "$cmd done"; unset A0 A1 A2 cmd'
2010-12-13 17:44:36
User: pipeliner
Functions: alias echo fg jobs read tail unset

make, find and a lot of other programs can take a lot of time. And can do not. Supppose you write a long, complicated command and wonder if it will be done in 3 seconds or 20 minutes. Just add "R" (without quotes) suffix to it and you can do other things: zsh will inform you when you can see the results.

You can replace zenity with other X Window dialogs program.

du . -mak|sort -n|tail -10
2010-12-03 19:28:55
User: georgesdev
Functions: du sort tail

du -m option to not go across mounts (you usually want to run that command to find what to destroy in that partition)

-a option to also list . files

-k to display in kilobytes

sort -n to sort in numerical order, biggest files last

tail -10 to only display biggest 10

ls -1t --group-directories-first /path/to/dir/ | tail -n 1
2010-12-02 12:25:16
User: fpunktk
Functions: ls tail

reverse the sorting of ls to get the newest file:

ls -1tr --group-directories-first /path/to/dir/ | tail -n 1


If there are no files in the directory you will get a directory or nothing.

tail -f /var/www/logs/domain.com.log | grep "POST /scripts/blog-post.php" | grep -v 192.168. | awk '{print $1}' | xargs -I{} iptables -I DDOS -s {} -j DROP
2010-11-30 06:22:18
User: tehusr
Functions: awk grep iptables tail xargs

Takes IP from web logs and pipes to iptables, use grep to white list IPs.. use if a particular file is getting requested by many different addresses.

Sure, its already down pipe and you bandwidth may suffer but that isnt the concern. This one liner saved me from all the traffic hitting the server a second time, reconfigure your system so your system will work like blog-post-1.php or the similar so legitimate users can continue working while the botnet kills itself.

tail -f file |xargs -IX printf "$(date -u)\t%s\n" X
tail -f file | awk '{now=strftime("%F %T%z\t");sub(/^/, now);print}'