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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 cat from sorted by
Terminal - Commands using cat - 443 results
tee >(cat - >&2)
2010-07-20 17:22:31
User: camocrazed
Functions: cat tee

the tee command does fine with file names, but not so much with file descriptors, such as &2 (stderr). This uses process redirection to tee to the specified descriptor.

In the sample output, it's being used to tee to stderr, which is connected with the terminal, and to wc -l, which is also outputting to the terminal. The result is the output of bash --version followed by the linecount

cat /proc/acpi/thermal_zone/THRM/temperature
2010-07-11 16:07:07
User: gunslinger_
Functions: cat
Tags: temperature

Displaying system temperature your system .

shellcode version @ http://inj3ct0r.com/exploits/12554

cat file_with_tabs.txt | perl -pe 's/\t/ /g'
2010-07-11 13:01:22
User: nikc
Functions: cat perl
Tags: cat perl replace

Replaces tabs in output with spaces. Uses perl since sed seems to work differently across platforms.

cat WAR_AND_PEACE_By_LeoTolstoi.txt | tr -cs "[:alnum:]" "\n"| tr "[:lower:]" "[:upper:]" | awk '{h[$1]++}END{for (i in h){print h[i]" "i}}'|sort -nr | cat -n | head -n 30
2010-07-05 06:39:20
User: cp
Functions: awk cat head sort tr


cat WAR_AND_PEACE_By_LeoTolstoi.txt | tr -cs "[:alnum:]" "\n"| tr "[:lower:]" "[:upper:]" | sort -S16M | uniq -c |sort -nr | cat -n | head -n 30

("sort -S1G" - Linux/GNU sort only) will also do the job but as some drawbacks (caused by space/time complexity of sorting) for bigger files...

cat my.ps | nc -q 1 hp4550.mynet.xx 9100
find /var/log/apache2 -name 'access.log*gz' -exec zcat {} \; -or -name 'access.log*' -exec cat {} \;
2010-06-19 08:35:12
User: recursiverse
Functions: cat find zcat

This command allows you to stream your log files, including gziped files, into one stream which can be piped to awk or some other command for analysis.

Note: if your version of 'find' supports it, use:

find /var/log/apache2 -name 'access.log*gz' -exec zcat {} + -or -name 'access.log*' -exec cat {} +
cat /proc/acpi/battery/*/state
cat VTS_05_1.VOB VTS_05_2.VOB VTS_05_3.VOB VTS_05_4.VOB > mergedmovie.mpg
cat /proc/acpi/battery/BAT0/state
cat /proc/acpi/ac_adapter/AC0/state
cat /proc/acpi/ac_adapter/ACAD/state
cat > {filename} {your text} [^C | ^D]
mysqldump -q --skip-opt --force --log-error=dbname_error.log -uroot -pmysqlpassword dbname | ssh -C [email protected] 'cd /path/to/backup/dir; cat > dbname.sql'
2010-05-29 23:06:04
User: esplinter
Functions: cat ssh

backup big mysql db to remote machine over ssh. "--skip-opt" option is needed when you can?t allocate full database in ram.

while [ 1 -lt 2 ]; do i=0; COL=$((RANDOM%$(tput cols)));ROW=$((RANDOM%$(tput cols)));while [ $i -lt $COL ]; do tput cup $i $ROW;echo -e "\033[1;34m" $(cat /dev/urandom | head -1 | cut -c1-1) 2>/dev/null ; i=$(expr $i + 1); done; done
2010-05-28 16:07:56
User: dave1010
Functions: cat cut expr head tput

Same as original, but works in bash

while :; do integer i=0; COL=$((RANDOM%$(tput cols))); ROW=$((RANDOM%$(tput cols))); while (( i <= COL)) do tput cup $i $ROW; echo "\033[1;34m" $(cat /dev/urandom | head -1 | cut -c1-1) 2>/dev/null; i=$(expr $i + 1); done done
cat > <file_name> << "EOF"
2010-05-27 12:06:30
User: sphere64
Functions: cat

1. Issue command

2. After angled bracket appears, enter file contents

3. When done, type "EOF"

cat /etc/*release
2010-05-26 11:58:34
User: dog
Functions: cat

Works on nearly all linux distros

cat file | sed -n -r '/^100$|^[0-9]{1,2}$/p'
2010-05-15 19:15:56
User: voyeg3r
Functions: cat file sed

-r to use extended regex

^ begin line

| alternative

get 100 or 0-9 one or two times

cat 1.tar.gz 2.tar.gz | tar zxvif -
2010-05-09 03:50:00
Functions: cat tar

You don't need to create an intermediate file, just pipe the output directly to tar command and use stin as file (put a dash after the f flag).

echo 'Host or [email protected]?:'; read newserver && ssh-keygen -N "" -t rsa -f ~/.ssh/id_rsa ; ssh $newserver cat <~/.ssh/id_rsa.pub ">>" ~/.ssh/authorized_keys ; ssh $newserver
2010-05-07 06:24:53
User: alf
Functions: cat echo read ssh ssh-keygen
Tags: ssh ssh-keygen

Some servers don't have ssh-copy-id, this works in those cases.

It will ask for the destination server, this can be IP, hostname, or [email protected] if different from current user.

Ssh keygen will let you know if a pubkey already exists on your system and you can opt to not overwrite it.

cat 1.tar.gz 2.tar.gz > 3.tar.gz; tar zxvfi 3.tar.gz
cat list|while read lines;do echo "USER admin">ftp;echo "PASS $lines">>ftp;echo "QUIT">>ftp;nc 21 <ftp>ftp2;echo "trying: $lines";cat ftp2|grep "230">/dev/null;[ "$?" -eq "0" ]&& echo "pass: $lines" && break;done
cat domainlist.txt | while read line; do echo -ne $line; whois $line | grep Expiration ; done | sed 's:Expiration Date::'
2010-05-02 06:49:09
User: netsaint
Functions: cat echo grep read sed whois

Create a text file called domainlist.txt with a domain per line, then run the command above. All registries are a little different, so play around with the command. Should produce a list of domains and their expirations date. I am responsible for my companies domains and have a dozen or so myself, so this is a quick check if I overlooked any.

for i in $(cat adm);do echo -e "GET /${i} HTTP/1.0\n\r\n\r \nHost:\r\n\r\n \nConnection: close\r\n"|nc -w 1 80 |grep -i "200 OK" 2>/dev/null >/dev/null;[ $? -eq "0" ] && echo "Found ${i}" && break;echo "$i";sleep 1;done
cat /sys/devices/virtual/dmi/id/board_name
2010-04-22 03:21:40
User: matthewbauer
Functions: cat

Prints the type of computer you have.

I think this should be used more in distros and other applications because it is so easy to get. This can also be asked by tutorials as an easy way to get your base hardware.

Some alternatives:

sudo dmidecode -s system-product-name


sudo smbios-sys-info-lite | sed -n 's/^Product Name: *\(.*\)/\1/p'