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Create iso image of cd/dvd

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"

Simple multi-user encrypted chat server for 5 users
Client ~$ ncat --ssl localhost 9876 Change localhost to the correct ip address.

a function to create a box of '=' characters around a given string.
First argument: string to put a box around. Second argument: character to use for box (default is '=') Same as command #4948, but shorter, and without the utility function.

Recursive search inside the content of files under current directory - then view the result paginated with 'less'
This command will traverse all of the folders and subfolders under current working directory. For every file inside it, it will do a search inside the content of the file for a specific term 'what'. Then it will print a list of the lines that contain that term (and match that pattern). Each matching line will be preceded with the path and name to the file and then the line number iside taht file wehre the pattern was found. Then the actual content of the matching lien will be printed. The output will be piped throug less, so that the user can scroll through it if it goes beyond the limits of the current display window.

Host cpu performance
Measure the cpu performance: In-case if the cpu is thermal throttling then you can find it using this command. Check the first line of the output. Example: Doing md5 for 3s on 16 size blocks: 11406892 md5's in 2.98s ? #(When cpu is not throttling) Doing md5 for 3s on 16 size blocks: 110692 md5's in 2.98s ?? #(When cpu is thermal throttling) Practical use case: Once we had cooling outage in data center which caused thermal throttling in some of the worker nodes. We used this tool to prove that some servers are not performing well because of the cpu thermal throttling.

Deal with dot files safely

Backup a directory structure
Copies a directory structure from /home/ to /backups/home (notice that the destination does not have a trailing slash)

Remove any RPMs matching a pattern
This should be an option to rpm, but isn't. I wind up using it a lot because I always forget the full name of the packages I want to delete.

lines in file2 that are not in file1


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