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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 awk from sorted by
Terminal - Commands using awk - 1,113 results
grep -e `date +%Y-%m-%d` /var/log/dpkg.log | awk '/install / {print $4}' | uniq | xargs apt-get -y remove
ps -ef | grep user | awk '{print $2}' | while read pid; do echo $pid ; pfiles $pid| grep portnum; done
2010-01-11 12:34:51
User: sharfah
Functions: awk echo grep ps read

My old Solaris server does not have lsof, so I have to use pfiles.

awk 'NR%3==1' file
2010-01-08 18:52:24
Functions: awk

A better way to show the file lines 3n + 1

awk '{print NR,$0}'
awk '{if (NR % 3 == 1) print $0}' foo > foo_every3_position1; awk '{if (NR % 3 == 2) print $0}' foo > foo_every3_position2; awk '{if (NR % 3 == 0) print $0}' foo > foo_every3_position3
2010-01-08 04:20:06
User: oshazard
Functions: awk

awk extract every nth line.

Generic is:

awk '{if (NR % LINE == POSITION) print $0}' foo

where "last" position is always 0 (zero).

awk 'BEGIN{while (a++<50) s=s "-"; print s}'
2010-01-06 16:16:35
User: SuperFly
Functions: awk

Change the number 50 to whatever number of characters you want. Change the character inside the double quotes to whatever you want printed.

for x in `ptree | awk '{print $1}'`; do pfiles $x | grep ${PORT} > /dev/null 2>&1; if [ x"$?" == "x0" ]; then ps -ef | grep $x | grep -v grep; fi; done 2> /dev/null
2010-01-05 17:02:23
User: bpfx
Functions: awk grep ps

Can use lsof, but since it's not part of the base OS, it's not always available.

pfiles -F /proc/* 2>/dev/null | awk '/^[0-9]+/{proc=$1};/[s]ockname: AF_INET/{print proc $0}'
2010-01-04 21:21:32
User: hunternet
Functions: awk

Command line to get which PID is opening a socket on IP and PORT.

Only useful under Solaris.

(bzcat BZIP2_FILES && cat TEXT_FILES) | grep -E "Invalid user|PAM" | grep -o -E "from .+" | awk '{print $2}' | sort | uniq >> /etc/hosts.deny
2010-01-03 04:41:51
User: jayhawkbabe
Functions: awk cat grep sort uniq

Searches all log files (including archived bzip2 files) for invalid user and PAM authentication errors, both of which are indicative of brute force attempts at logging into computer. A list of all unique IP addresses and domain names is appended to hosts.deny. The command (and grep error messages) will work on Mac OS X 10.6, small adjustments may be needed for other OSs.

BACKUP_FILE_SIZE=`eval ls -l ${BACKUP_FILE} | awk {'print $5'}`; if [ $BACKUP_FILE_SIZE -le 20 ]; then echo "its empty"; else echo "its not empty"; fi
2009-12-29 08:34:37
User: Redrocket
Functions: awk echo ls

If you gzip an empty file it becomes 20 bytes. Some backup checks i do check to see if the file is greater than zero size (-s flag) but this is no good here. Im sure someone has a better check than me for this? No check to see if file exists before checking it's size.

calc() { awk 'BEGIN { OFMT="%f"; print '"$*"'; exit}'; }
$class=ExampleClass; $path=src; for constant in `grep ' const ' $class.php | awk '{print $2;}'`; do grep -r "$class::$constant" $path; done
DIR=. ; FSTYPE=$(df -TP ${DIR} | grep -v Type | awk '{ print $2 }') ; echo "${FSTYPE}"
2009-12-22 14:01:50
User: unixhome
Functions: awk df echo grep

Exclude 400 client hosts with NFS auto-mounted home directories.

Easily modified for inclusion in your scripts.

curl -s search.twitter.com | awk -F'</?[^>]+>' '/\/intra\/trend\//{print $2}'
curl --silent search.twitter.com | sed -n '/div id=\"hot\"/,/div/p' | awk -F\> '{print $2}' | awk -F\< '{print $1}' | sed '/^$/d'
ps -ylC httpd --sort:rss | awk '{ SUM += $8 } END { print SUM/1024 }'
2009-12-20 15:41:50
User: nasser
Functions: awk ps

This command will show you amount of memory used by apache

awk '!x[$0]++' <file>
2009-12-20 02:33:21
User: din7
Functions: awk

Using awk, find duplicates in a file without sorting, which reorders the contents. awk will not reorder them, and still find and remove duplicates which you can then redirect into another file.

awk '/.*{$/{s[$1]=z[$1]=j+0}{l[j++]=$0}END{asorti(s);for(v in s){while(l[z[s[v]]]!~/}$/)print l[z[s[v]]++];print"}"ORS}}'
tar -cf - . | pv -s $(du -sb . | awk '{print $1}') | gzip > out.tgz
2009-12-18 17:09:08
User: opertinicy
Functions: awk du gzip tar

What happens here is we tell tar to create "-c" an archive of all files in current dir "." (recursively) and output the data to stdout "-f -". Next we specify the size "-s" to pv of all files in current dir. The "du -sb . | awk ?{print $1}?" returns number of bytes in current dir, and it gets fed as "-s" parameter to pv. Next we gzip the whole content and output the result to out.tgz file. This way "pv" knows how much data is still left to be processed and shows us that it will take yet another 4 mins 49 secs to finish.

Credit: Peteris Krumins http://www.catonmat.net/blog/unix-utilities-pipe-viewer/

awk -F":" '{ print $1 }' /etc/passwd | while read UU ; do STATUS=$(passwd -S ${UU} | grep locked 2>/dev/null) ; if [[ ! -z ${STATUS} ]] ; then echo "Account ${UU} is locked." ; fi ; done
echo $LS_COLORS | sed 's/:/\n/g' | awk -F= '!/^$/{printf("%s \x1b[%smdemo\x1b[0m\n",$0,$2)}'
2009-12-15 01:17:46
User: bones7456
Functions: awk echo sed

This can show all ls colors, with a demo.

zcat access_log.*.gz | awk '{print $7}' | sort | uniq -c | sort -n | tail -n 20
curl -sL 'dynamic.xkcd.com/comic/random/' | awk -F\" '/^<img/{printf("<?xml version=\"1.0\"?>\n<xkcd>\n<item>\n <title>%s</title>\n <comment>%s</comment>\n <image>%s</image>\n</item>\n</xkcd>\n", $6, $4, $2)}'
wget -q http://dynamic.xkcd.com/comic/random/ -O-| sed -n '/<img src="http:\/\/imgs.xkcd.com\/comics/{s/.*\(http:.*\)" t.*/\1/;p}' | awk '{system ("wget -q " $1 " -O- | display -title $(basename " $1") -write /tmp/$(basename " $1")");}'
2009-12-09 13:41:25
User: laugg
Functions: awk sed wget
Tags: sed awk wget comic

Only need to install Image Magick package.

Display a xkcd comic with its title and save it in /tmp directory

If you prefer to view the newest xkcd, use this command:

wget -q http://xkcd.com/ -O-| sed -n '/<img src="http:\/\/imgs.xkcd.com\/comics/{s/.*\(http:.*\)" t.*/\1/;p}' | awk '{system ("wget -q " $1 " -O- | display -title $(basename " $1") -write /tmp/$(basename " $1")");}'
traceroute 2>/dev/null -n google.com | awk '/^ *1/{print $2;exit}'