commandlinefu.com is the place to record those command-line gems that you return to again and again.
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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.
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,…):
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See who is using a specific port. Especially when you're using AIX. In Ubuntu, for example, this can easily be seen with the netstat command.
Only the number of calls nothing else.
Use the excellent sensiblepasswords.com to a generate random (yet easy-to-remember) password every second, and copy it to the clipboard. Useful for generating a list of passwords and pasting them into a spreadsheet.
This script uses "madebynathan"'s "cb" function (http://madebynathan.com/2011/10/04/a-nicer-way-to-use-xclip/); you could also replace "cb" with
xclip -selection c
Remove "while true; do" and "; done" to generate and copy only 1 password.
Overwrite all sectors with zeros in one pass with ETA and speed status. If you wish to do more passes, encapsulate the line in a for loop (7 pass example):
for f in `seq 1 7`; do pv -s `fdisk -l /dev/sdX|grep "Disk /"|cut -d' ' -f5` /dev/zero >/dev/sdX ; done
Note: Substitute /dev/sdX with the correct drive you wish to erase. Also, you may have to be root to execute the command.
KDE Development Platform: 4.7.3 (4.7.3)
KIO Client: 2.0
This is a handy command to put into ~/.bash_logout to automatically un-mount windows shares whenever the user logs out. If you use this on as a non-root account then you'll need to append sudo before umount and the user will need to have the appropriate sudoer rights to run the /bin/umount command.
Search in decimal rather than hex. od dumps the character list, cut to remove offsets, sort -u gives the used characters. seq gives the comparison list, but we need this sorted alphabetically for comm, which does the filtering. I drop to perl to convert back to characters (is there a better way?) and then use od to dump them in a print-safe format.
poor man's xml parser :)
Output: integer x , 1>=x
Able to reproduce on the same host
Acceptable for output to be different among OSes (Solaris, Linux, BSD)
Useful for providing DayOfMonth splay in cron jobs. Capped at 28 for Febtober.
Better awk example, using only mplayer, grep, cut, and awk.
* ps -ef # list running processes
* grep string
* pull the process names from 8th field
* cut and delimiter '/'
* print 4th field
* get rid of trailing grep
* for loop killall -9 $i which is the process name
Why remember? Generate!
Up to 48 chars, works on any unix-like system (NB: BSD use md5 instead of md5sum)
If you don't have html2text
Display the serial of the iPhone (aka UDID).
This command shows a sorted list of the IP addresses from which there have been authentication errors via SSH (possible script kiddies trying to gain access to your server), it eliminates duplicates so it's easier to read, but you can remove the "uniq" command at the end, or even do a "uniq -c" to have a count of how many times each IP address shows in the log (the path to the log may vary from system to system)