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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.

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When was your OS installed?
Show time and date when you installed your OS.

Look for English words in /dev/urandom
Little faster alternative.

Convert from octal format to umask
Umask is obtained subtracting 7 from each cypher of octal format. I store octal perm format in an array,then for each element of array I subtract 7. The result is the umask.

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"

Clean up display when the bash prompt is displayed
This will cause bash to fix a garbled terminal before the prompt is printed. For example, if you cat a file with nonprintable character sequences, the terminal sometimes ends up in a mode where it only prints line drawing characters. This sequence will return the terminal to the standard character set after every command.

ssh autocomplete
Add to your bash profile to minimize carpal tunnel syndrome. Doesn't work with user@hostname but appending "-l user" works fine if needed. Works for ping as well.. complete -W "$(echo `cat ~/.ssh/known_hosts | cut -f 1 -d ' ' | sed -e s/,.*//g | uniq | grep -v "\["`;)" ping

Gets directory and files tree listing from a FTP-server
Creates a file with contents like `du -a`, only it is remote server filesystem hierarchy. Very usefull then for grep-ing without remote connection.

clean up memory on linux
where proc filesystem mounted under /proc

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

List out classes in of all htmls in directory
Lists out all classes used in all *.html files in the currect directory. usefull for checking if you have left out any style definitions, or accidentally given a different name than you intended. ( I have an ugly habit of accidentally substituting camelCase instead of using under_scores: i would name soemthing counterBox instead of counter_box) WARNING: assumes you give classnames in between double quotes, and that you apply only one class per element.


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