Commands by ozymandias (2)

  • In my work environment, we log onto the servers as our user ('user', in the sample ouput), and 'sudo su - root' to other accounts. This trick allows us to return the account name we logged in as -- and not the account name we currently are ('root', in this example). Using this trick, you can build other commands: Set your CVSROOT env variable to your account name: CVSROOT=$(who am i | awk '{print $1}')@cvs.server.example.com:/cvsroot SCP a file to another server: scp file.txt $(who am i | awk '{print $1}')@some.other.server.com:. This works out great in my environment, as we can include this in our documentation and make the comands more easy to copy/paste for different users, and not have to set all sorts of variables, or modify the docs for each user. whoami gives you the name of the user you currently are, not the user you logged on originally as. who gives you a listing of every single person logged onto the server. who am i gives you the name of the user you logged on as, and not who you changed to with su. Look at the following scenario: whoami user su - # whoami root # who am i user pts/51 2009-02-13 10:24 (:0.0) whoami != who am i Show Sample Output


    -18
    who am i
    ozymandias · 2009-02-20 16:26:11 12
  • The expansion {,} in bash will repeat the given string once for each item seperated by commas. The given command will result in the following being run: cp /really/long/path/and/file/name /really/long/path/and/file/name-`date -I` These can be embedded as needed, ex: rm file{1,2,3{1,2,3}} would delete the files file1, file2, file31, file32, file32, and no other files.


    4
    cp /really/long/path/and/file/name{,-`date -I`}
    ozymandias · 2009-02-18 20:35:47 6

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 files recursively by size

Email someone if a web page has been updated.
A cronjob command line to email someone when a webpages homepage is updated.

Stat each file in a directory
This will run stat on each file in the directory.

ignore .DS_Store forever in GIT
With a couple of little commands, you?ll be able to ignore the .DS_Store files forever from your git repositories on mac! The following command will add the .gitignore file to the git configuration git config --global core.excludesfile ~/.gitignore then, the following, will add the .DS_Store to the list echo .DS_Store >> ~/.gitignore

Repeatedly purge orphaned packages on Debian-like Linuxes
Upgraded Debian/Ubuntu/etc. systems may have a number of "orphaned" packages which are just taking up space, which can be found with the "deborphan" command. While you could just do "dpkg --purge $(deborphan)", the act of purging orphans will often create more orphans. This command will get them all in one shot.

drill holes on image

Cut out a piece of film from a file. Choose an arbitrary length and starting time.
With: -vcodec, you choose what video codec the new file should be encoded with. Run ffmpeg -formats E to list all available video and audio encoders and file formats. copy, you choose the video encoder that just copies the file. -acodec, you choose what audio codec the new file should be encoded with. copy, you choose the audio encoder that just copies the file. -i originalfile, you provide the filename of the original file to ffmpeg -ss 00:01:30, you choose the starting time on the original file in this case 1 min and 30 seconds into the film -t 0:0:20, you choose the length of the new film newfile, you choose the name of the file created. Here is more information of how to use ffmpeg: http://www.ffmpeg.org/ffmpeg-doc.html

Delete .svn directories and content recursively
Use carefully have rm -rf ;-)

Shows size of dirs and files, hidden or not, sorted.
Enhanced version: fixes sorting by human readable numbers, and filters out non MB or GB entries that have a G or an M in their name.

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.


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: