All commands (14,187)

What's this?

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

Share Your Commands


Check These Out

Function to output an ASCII character given its decimal equivalent
I've corrected the function. My octal conversion formula was completely wrong. Thanks to pgas at http://mywiki.wooledge.org/BashFAQ/071 for setting me straight. The new function is from pgas and is very fast.

Rename .JPG to .jpg recursively
This command is useful for renaming a clipart, pic gallery or your photo collection. It will only change the big caps to small ones (on the extension).

Equivalent to ifconfig -a in HPUX

Schedule a script or command in x num hours, silently run in the background even if logged out
This is helpful for shell scripts, I use it in my custom php install script to schedule to delete the build files in 3 hours, as the php install script is completely automated and is made to run slow. Does require at, which some environments without crontab still do have. You can add as many commands to the at you want. Here's how I delete them in case the script gets killed. (trapped) atq |awk '{print $1}'|xargs -iJ atrm J &>/dev/null

randomize hostname and mac address, force dhcp renew. (for anonymous networking)
this string of commands will release your dhcp address, change your mac address, generate a new random hostname and then get a new dhcp lease.

File rotation without rename command
Rotates log files with "gz"-extension in a directory for 7 days and enumerates the number in file name. i.e.: logfile.1.gz > logfile.2.gz I needed this line due to the limitations on AIX Unix systems which do not ship with the rename command.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Show directories in the PATH, one per line
Shorter version.

strace like SystemTap script
The stap script is : #! /usr/bin/env stap probe syscall.* { if (pid() == target()) printf("%s %s\n", name, argstr); }

Sort netflow packet capture
Sort netflow packet capture by unique connections excluding source port.


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: