Hide

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.

OpenID
or
Sign in Register

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Hide

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:

Hide

News

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.
Hide

Tags

Hide

Functions

Hide

Credits

Site by David Winterbottom (user root).

Commands using awk from sorted by
Terminal - Commands using awk - 1,112 results
while true; do X=$Y; sleep 1; Y=$(ifconfig eth0|grep RX\ bytes|awk '{ print $2 }'|cut -d : -f 2); echo "$(( Y-X )) bps"; done
2009-03-27 08:26:39
User: stuntdawg
Functions: awk cut echo grep ifconfig sleep
Tags: bash Linux ifconfig
10
Up
Down
Measures download speed on eth0
Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
arp -s $(route -n | awk '/^0.0.0.0/ {print $2}') \ $(arp -n | grep `route -n | awk '/^0.0.0.0/ {print $2}'`| awk '{print $3}')
2009-03-25 09:53:10
User: aramosf
Functions: arp awk grep route
Tags: Network Security
2
Up
Down
add static arp entry to default gateway, arp poison protection
Comments (3) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
awk '{sum+=$1; sumsq+=$1*$1} END {print sqrt(sumsq/NR - (sum/NR)**2)}' file.dat
2009-03-24 21:56:40
User: kaan
Functions: awk
Tags: awk
6
Up
Down
Display the standard deviation of a column of numbers with awk
Comments (4) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
seq 0 0.1 20 | awk '{print $1, cos(0.5*$1)*sin(5*$1)}' | graph -T X
2009-03-24 21:46:59
User: kaan
Functions: awk seq
Tags: awk graph plotutils
2
Up
Down
Quick plotting of a function

The arguments of "seq" indicate the starting value, step size, and the end value of the x-range. "awk" outputs (x, f(x)) pairs and pipes them to "graph", which is part of the "plotutils" package.

Comments (3) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
seq 6 | awk '{for(x=1; x<=5; x++) {printf ("%f ", rand())}; printf ("\n")}'
2009-03-24 21:33:38
User: kaan
Functions: awk printf seq
Tags: awk seq
3
Up
Down
Display rows and columns of random numbers with awk

Displays six rows and five columns of random numbers between 0 and 1. If you need only one column, you can dispense with the "for" loop.

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
awk '{sum1+=$1; sum2+=$2} END {print sum1/NR, sum2/NR}' file.dat
2009-03-24 21:22:14
User: kaan
Functions: awk
Tags: awk
2
Up
Down
Averaging columns of numbers

This example calculates the averages of column one and column two of "file.dat". It can be easily modified if other columns are to be averaged.

Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
seq 50| awk 'BEGIN {a=1; b=1} {print a; c=a+b; a=b; b=c}'
2009-03-24 20:39:24
User: kaan
Functions: awk seq
Tags: awk seq
13
Up
Down
Fibonacci numbers with awk

Another combination of seq and awk. Not very efficient, but sufficiently quick.

Show sample output | Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
seq 100 | awk '{sum+=$1} END {print sum}'
2009-03-24 20:30:40
User: kaan
Functions: awk seq
Tags: awk seq
4
Up
Down
Calculating series with awk: add numbers from 1 to 100

"seq 100" outputs 1,2,..,100, separated by newlines. awk adds them up and displays the sum.

"seq 1 2 11" outputs 1,3,..,11.

Variations:

1+3+...+(2n-1) = n^2

seq 1 2 19 | awk '{sum+=$1} END {print sum}' # displays 100

1/2 + 1/4 + ... = 1

seq 10 | awk '{sum+=1/(2**$1)} END {print sum}' # displays 0.999023
Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ps ax | grep <processname> | grep -v grep | awk '{print $1}' | sudo xargs kill -9
2009-03-24 19:52:47
User: copyhacker
Functions: awk grep kill ps sudo xargs
-5
Up
Down
Kill a bunch of processes with the same name
Comments (5) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
/usr/sbin/arp -i eth0 | awk '{print $3}' | sed 1d
2009-03-24 18:53:26
User: prayer
Functions: awk sed
Tags: Network
-1
Up
Down
List nearbies
Comments (1) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ps aux | grep 'httpd ' | awk {'print $2'} | xargs kill -9
2009-03-23 16:15:06
User: thisduck
Functions: awk grep kill ps xargs
Tags: kill
-5
Up
Down
kills all processes for a certain program e.g. httpd
Comments (6) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
mysql --database=dbname -B -N -e "SHOW TABLES" | awk '{print "ALTER TABLE", $1, "CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;"}' | mysql --database=dbname &
2009-03-21 18:45:15
User: root
Functions: awk
Tags: mysql
17
Up
Down
Convert all MySQL tables and fields to UTF8

This loops through all tables and changes their collations to UTF8. You should backup beforehand though in case some data is lost in the process.

Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
sudo zcat /var/log/auth.log.*.gz | awk '/Failed password/&&!/for invalid user/{a[$9]++}/Failed password for invalid user/{a["*" $11]++}END{for (i in a) printf "%6s\t%s\n", a[i], i|"sort -n"}'
2009-03-21 06:41:59
User: point_to_null
Functions: awk printf sudo zcat
Tags: Security awk brute force
22
Up
Down
Brute force discover

Show the number of failed tries of login per account. If the user does not exist it is marked with *.

Show sample output | Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ropened='p4 opened | awk -F# "{print \$1}" | p4 -x - revert'
2009-03-20 11:10:47
User: Alexander
Functions: awk
Tags: p4 SCM Perforce
1
Up
Down
Revert back all files currently checked out by Perforce SCM for edit
Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
alias opened='p4 opened | awk -F# "{print \$1}"'
2009-03-20 11:06:41
User: Alexander
Functions: alias awk
Tags: p4 SCM Perforce
0
Up
Down
Print the list of all files checked out by Perforce SCM

Just type 'opened' and get all files currently opened for edit.

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
vos listvldb | agrep LOCKED -d RWrite | grep RWrite: | awk -F: '{print $2}' | awk '{printf("%s ",$1)} END {printf("\n")}'
2009-03-17 19:55:39
User: mpb
Functions: awk grep
0
Up
Down
Display list of locked AFS volumes (if any)

This command shows if there are any locked AFS volumes.

The output is a list of AFS volume IDs (or nothing if there are none locked).

Show sample output | Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
cat count.txt | awk '{ sum+=$1} END {print sum}'
2009-03-16 00:22:13
User: duxklr
Functions: awk cat
Tags: awk
15
Up
Down
Using awk to sum/count a column of numbers.

Takes a input file (count.txt) that looks like:

1

2

3

4

5

It will add/sum the first column of numbers.

Comments (7) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ls -1 | grep " " | awk '{printf("mv \"%s\" ",$0); gsub(/ /,"_",$0); printf("%s\n",$0)}' | sh # rename filenames: spaces to "_"
2009-03-15 18:42:43
User: mpb
Functions: awk grep ls rename sh
2
Up
Down
Convert embedded spaces in filenames to "_" (underscore)

This command converts filenames with embedded spaces in the current directory replacing spaces with the underscore ("_") character.

Show sample output | Comments (13) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
ls -l|awk '{print $6,$8}'|sort -d
2009-03-13 19:00:18
User: archlich
Functions: awk ls sort
-4
Up
Down
display most recently modified files

Can pipe to tail or change the awk for for file size, groups, users, etc.

Show sample output | Comments (4) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
lsof|grep /somemount/| awk '{print $2}'|xargs kill
2009-03-12 18:42:19
User: archlich
Functions: awk grep xargs
4
Up
Down
kill all processes using a directory/file/etc

This command will kill all processes using a directory. It's quick and dirty. One may also use a -9 with kill in case regular kill doesn't work. This is useful if one needs to umount a directory.

Show sample output | Comments (3) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
svn status | grep "^\?" | awk '{print $2}' | xargs svn add
2009-03-12 15:06:12
User: unixfu73000
Functions: awk grep xargs
Tags: svn
-1
Up
Down
SVN Add Recursively

This adds all new files to SVN recursively. It doesn't work for files that have spaces in their name, but why would you create a file with a space in its name in the first place?

Comments (4) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
svn status | grep ^? | awk '{print $2}' | xargs rm -rf
2009-03-10 17:01:40
User: Highwayman
Functions: awk grep rm xargs
1
Up
Down
SVN Clean

Removes all unversioned files and folders from an svn repository. Also:

svn status --no-ignore | grep ^I | awk '{print $2}' | xargs rm -rf

will remove those files which svn status ignores. Handy to add to a script which is in your path so you can run it from any repository (a la 'svn_clean.sh').

Comments (4) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
grep Mar/2009 /var/log/apache2/access.log | awk '{ print $1 }' | sort -n | uniq -c | sort -rn | head
2009-03-10 16:46:19
User: allinurl
Functions: awk grep sort uniq
4
Up
Down
grep apache access.log and list IP's by hits and date - sorted
Comments (4) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
echo -n $mypass | md5sum | awk {'print $1'}
2009-03-10 13:12:21
User: tororebelde
Functions: awk echo md5sum
1
Up
Down
Create a random password encrypted with md5 with custom lenght

This was useful to generate random passwords to some webpage users, using the sample code, inside a bash script

Show sample output | Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate
awk '{ for (f = 1; f <= NF; f++) a[NR, f] = $f } NF > nf { nf = NF } END { for (f = 1; f <= nf; f++) for (r = 1; r <= NR; r++) printf a[r, f] (r==NR ? RS : FS) }'
2009-03-10 05:35:22
User: MSBF
Functions: awk printf
0
Up
Down
transpose a file

works the same as R's t()

Comments (0) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate