Commands by asdf (0)

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remove all spaces from all files in current folder

find and reduce 8x parallel the size of JPG images without loosing quality via jpegoptim

Go to parent directory of filename edited in last command
Uses the last argument of the last executed command, and gets the directory name from it. Use $!:t for the filename alone, without the dirname.

Check for login failures and summarize
This command checks for the number of times when someone has tried to login to your server and failed. If there are a lot, then that user is being targeted on your system and you might want to make sure that user either has remote logins disabled, or has a strong password, or both. If your output has an "invalid" line, it is a summary of all logins from users that don't exist on your system.

show the date every rpm was installed
the newest rpms are at the top; individual packages can also be queried this way: rpm --last -q package

Create a bash script from last n commands
Uses history to get the last n+1 commands (since this command will appear as the most recent), then strips out the line number and this command using sed, and appends the commands to a file.

Screen enable/disable loggin in all windows
The command when added in screenrc enables logging all open windows by using the C-l (control-l key combination) and disable by C-o . The lines need to be added in separate lines .

Bare Metal IRC Client
Uses the extremely cool utilities netcat and expect. "expect" logs in & monitors for server PING checks. When a PING is received it sends the PONG needed to stay connected. IRC commands to try: HELP, TIME, MOTD, JOIN and PRIVMSG The "/" in front of IRC commands are not needed, e.g. type JOIN #mygroup Learn about expect: http://tldp.org/LDP/LGNET/issue48/fisher.html The sample output shows snippets from an actual IRC session. Please click UP button if you like it!

statistics in one line
In this example, file contains five columns where first column is text. Variance is calculated for columns 2 - 5 by using perl module Statistics::Descriptive. There are many more statistical functions available in the module.

add a backup (or any other) suffix to a file
Very helpful when you've got complex filenames and needs to change just some small parts of it. Renaming a file called "i-made-a-small-typo-right-here" to "i-made-a-big-typo-right-here": $ mv -vi i-made-a-{small,big}-typo-right-here You could also copy multiple files, edit, remove, process, etc.


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