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Diff on two variables
You got some results in two variables within your shell script and would like to find the differences? Changes in process lists, reworked file contents, ... . No need to write to temporary files. You can use all the diff parameters you'll need. Maybe anything like $ grep "^>" is helpful afterwards.

The program listening on port 8080 through IPv6

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"

Show current iptables rules, with line numbers

Perform a C-style loop in Bash.
Print 0 through 99, each on a separate line.

Make a playlistfile for mpg321 or other CLI player
Supports other file formats.

Compute the numeric sum of a file
In the file data.txt there is a single column of numbers. Sed adds a "+" between lines and xargs prepares the output for bc. The "echo 0" is to avoid to have a "+" at the beginning of the line.

Start another X session in a window
You might have Xnest (older) rather than Xephyr. You can experiment with other desktops eg: startx /usr/bin/start-kde -- /usr/bin/Xephyr :2 You can start X on a remote machine (although I'd recommend vnc for anything slower than a LAN): startx /usr/bin/ssh -X gnome-session -- /usr/bin/Xephyr :2 Or just start another X session locally talking to the remote backend:

Identify long lines in a file
This command displays a list of lines that are longer than 72 characters. I use this command to identify those lines in my scripts and cut them short the way I like it.

Add all files in current directory to SVN
The --force option bypasses the warning if files are already in SVN.


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