Commands by dewaynewilliams (0)

  • …
    bash: commands not found

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 open files that have no links to them on the filesystem
I have come across a situation in the past where someone has unlinked a file by running an 'rm' command against it while it was still being written to by a running process. The problem manifested itself when a 'df' command showed a filesystem at 100%, but this did not match the total value of a 'du -sk *'. When this happens, the process continues to write to the file but you can no longer see the file on the filesystem. Stopping and starting the process will, more often than not, get rid of the unlinked file, however this is not always possible on a live server. When you are in this situation you can use the 'lsof' command above to get the PID of the process that owns the file (in the sample output this is 23521). Run the following command to see a sym-link to the file (marked as deleted): $ cd /proc/23521/fd && ls -l Truncate the sym-link to regain your disk space: $ > /proc/23521/fd/3 I should point out that this is pretty brutal and *could* potentially destabilise your system depending on what process the file belongs to that you are truncating.

Set RGB gamma of secondary monitor
This command first determines whether a second screen is connected. If this is the case, it sets the screen's RGB gamma via xrandr. Useful for cheap or slightly defective monitors with a tint. In this example a yellowing/champagne color deviation is compensated for by decreasing the red and the green portion of the image.

split and combine different pages from different pdf's
The command shows the real power of the pdftk tool, you can do basically everything you want with multiple pdf's. In the command a book is created from chapters, headings and covers.

memcache affinity: queries local memcached for stats, calculates hit/get ratio and prints it out.
queries local memcached for stats, calculates hit/get ratio and prints it out.

Human readable directory sizes for current directory, sorted descending

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

list block devices
Shows all block devices in a tree with descruptions of what they are.

floating point operations in shell scripts
using bc is for sissies. dc is much better :-D Polish notation will rule the world...

Search some text from all files inside a directory

Remove text from file1 which is in file2 and stores it in an other file
This command compares file2 with file1 and removes the lines that are in file1 from file2. Handy if you have a file where file1 was the origional and you want to remove the origional data from your file2.

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: