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commandlinefu.com is the place to record those command-line gems that you return to again and again.

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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

All commands from sorted by
Terminal - All commands - 12,404 results
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.

find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate
2009-09-21 00:24:14
User: syssyphus
Functions: find md5sum sort uniq xargs

This dup finder saves time by comparing size first, then md5sum, it doesn't delete anything, just lists them.

python -m smtpd -n -c DebuggingServer localhost:1025
2009-02-05 16:50:44
User: jemerick
Functions: python

This command will start a simple SMTP server listening on port 1025 of localhost. This server simply prints to standard output all email headers and the email body.

2010-05-15 15:12:47
User: new_user
Tags: bash edit
/usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.google.com/


!:- http://www.commandlinefu.com/

is the same as

/usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.commandlinefu.com/
cat /etc/issue
ssh-copy-id [email protected]
wget -qO - "http://www.tarball.com/tarball.gz" | tar zxvf -
translate(){ wget -qO- "http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=$1&langpair=$2|${3:-en}" | sed 's/.*"translatedText":"\([^"]*\)".*}/\1\n/'; }
2010-03-08 03:15:48
User: matthewbauer
Functions: sed wget


translate <phrase> <source-language> <output-language>


translate hello en es

See this for a list of language codes:


ps aux | grep [p]rocess-name
2009-08-13 05:44:45
User: olorin
Functions: grep ps

As an alternative to using an additional grep -v grep you can use a simple regular expression in the search pattern (first letter is something out of the single letter list ;-)) to drop the grep command itself.

tr -c "[:digit:]" " " < /dev/urandom | dd cbs=$COLUMNS conv=unblock | GREP_COLOR="1;32" grep --color "[^ ]"
2009-06-14 21:17:40
User: Josay
Tags: completion ESC

Pressing ESC then * will insert in the command line the results of the autocompletion.

It's hard to explain but if you look the sample output or do

echo ESC *

you will understand quickly.

By the way, few reminders about ESC :

- Hold ESC does the same thing as tab tab

- 'ESC .' inserts the last argument of last command (can be done many times in order to get the last argument of all previous commands)

mplayer -ao pcm -vo null -vc dummy -dumpaudio -dumpfile <output-file> <input-file>
cat ~/.ssh/id_rsa.pub | ssh [email protected] "mkdir ~/.ssh; cat >> ~/.ssh/authorized_keys"
2009-02-05 19:37:56
User: DEinspanjer
Functions: cat ssh

If you use Mac OS X or some other *nix variant that doesn't come with ssh-copy-id, this one-liner will allow you to add your public key to a remote machine so you can subsequently ssh to that machine without a password.

rename 'y/ /_/' *
2009-06-27 22:20:47
User: signal9
Functions: rename
Tags: file rename

This command will replace all the spaces in all the filenames of the current directory with underscores. There are other commands that do this here, but this one is the easiest and shortest.

readom dev=/dev/scd0 f=/path/to/image.iso
2009-03-08 13:21:23
User: atoponce

Many like to use 'dd' for creating CD/DVD iso images. This is bad. Very bad. The reason this is, is 'dd' doesn't have any built-in error checking. So, you don't know if you got all the bits or not. As such, it is not the right tool for the job. Instead, 'reaom' (read optical media) from the wodim package is what you should be using. It has built-in error checking. Similarly, if you want to burn your newly creating ISO, stay away from 'dd', and use:

wodim -v -eject /path/to/image.iso
? () { echo "$*" | bc -l; }
2009-06-28 20:15:30
User: fizz
Functions: bc echo

defines a handy function for quick calculations from cli.

once defined:

? 10*2+3
i="8uyxVmdaJ-w";mplayer -fs $(curl -s "http://www.youtube.com/get_video_info?&video_id=$i" | echo -e $(sed 's/%/\\x/g;s/.*\(v[0-9]\.lscache.*\)/http:\/\/\1/g') | grep -oP '^[^|,]*')
2009-03-09 03:57:44
User: lrvick
Functions: echo grep sed

This is the result of a several week venture without X. I found myself totally happy without X (and by extension without flash) and was able to do just about anything but watch YouTube videos... so this a the solution I came up with for that. I am sure this can be done better but this does indeed work... and tends to work far better than YouTube's ghetto proprietary flash player ;-)

Replace $i with any YouTube ID you want and this will scrape the site for the _real_ URL to the full quality .FLV file on Youtube's server and will then will hand that over to mplayer (or vlc or whatever you want) to be streamed.

In some browsers you can replace $i with just a % or put this in a shell script so all YouTube IDs can be handed directly off to your media player of choice for true streaming without the need for Flash or a downloader like clive. (I do however fully recommend clive if you wish to archive videos instead of streaming them)

If any interest is shown I would be more than happy to provide similar commands for other sites. Most streaming flash players use similar logic to YouTube.

Edit: 05/03/2011 -

Updated line to work with current YouTube. It could be a lot prettier but I will probably follow up with another update when I figure out how to get rid of that pesky Grep. Sed should take that syntax... but it doesn't.

Original (no longer working) command:

mplayer -fs $(echo "http://youtube.com/get_video.php?$(curl -s $youtube_url | sed -n "/watch_fullscreen/s;.*\(video_id.\+\)&title.*;\1;p")")

strace -ff -e trace=write -e write=1,2 -p SOME_PID
ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/ /' -e 's/-/|/'
2009-02-15 20:43:21
Functions: grep ls sed

Prints a graphical directory tree from your current directory

alias 'ps?'='ps ax | grep '
pv sourcefile > destfile
2010-03-20 20:55:18
User: edo
Tags: pv

pv allows a user to see the progress of data through a pipeline, by giving information such as time elapsed, percentage completed (with progress bar), current throughput rate, total data transferred, and ETA. (man pv)

git add -u
2009-09-16 00:13:14
User: donnoman
Tags: git

It deletes all removed files, updates what was modified, and adds new files.

mkdir -p a/long/directory/path
2009-02-07 15:26:27
User: tjweir
Functions: mkdir

This will create the intermediate directories that do not exist.

I did not know about this for a long time.