Commands by gnugr (2)

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

List the popular module namespaces on CPAN
Grabs the complete module list from CPAN, pulls the first column, ditches html lines, counts, ditches small namespaces.

Create an animated gif from a Youtube video
requires "youtube-dl" -- sure you can do this with wget and some more obscurity but why waste your time when this great tool is available? the guts consist of mplayer converting a video to a gif -- study this command and read the man page for more information $ mplayer video.flv -ss 00:23 -endpos 6 -vo gif89a:fps=5:output=output.gif -vf scale=400:300 -nosound generates a 6 second gif starting at 23 seconds of play time at 5 fps and a scale of 400x300 start time (-ss)/end time (-endpos) formats: 00:00:00.000 end time should be relative to start time, not absolute. i.e. -endpos 5 == seconds after 0:42 = 0:47 end point play with fps and scale for lower gif sizes the subshell is a solution for the -b flag on youtube-dl which downloads the best quality video, sometimes, which can be various video formats $(ls ${url##*=}*| tail -n1)

The top ten commands you use

Get list of servers with a specific port open
Change the -p argument for the port number. See "man nmap" for different ways to specify address ranges.

reverse order of file
awk reverse order of lines (emulates "tac")

generate random password (works on Mac OS X)
Prepending env LC_CTYPE=C fixes a problem with bad bytes in /dev/urandom on Mac OS X

Nicely display permissions in octal format with filename
Nicely display permissions in octal format and filename for a given directory

Mouse Tracking
Will track your mouse and save it to a file. You can use gnuplot to graph it: $ gnuplot -persist

Converts uppercase chars in a string to lowercase

Make vim open in tabs by default (save to .profile)
I always add this to my .profile rc so I can do things like: "vim *.c" and the files are opened in tabs.

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: