Commands by kmac (4)

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Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

get all Google ipv4/6 subnets for a iptables firewall for example (updated version)
google has added 2 more netblocks...

Generate White Noise
This command will generate white noise through your speakers (assuming you have sound enabled). It's good for staying focused, privacy, coping with tinnitus, etc. I use it to test that the sound works.

HDD Performance Write Test
Test your XFS filesystem and Raptor hard drives for write performance.

Random line from bash.org (funny IRC quotes)
bash.org is a collection of funny quotes from IRC. WARNING: some of the quotes contain "adult" jokes... may be embarrassing if your boss sees them... Thanks to Chen for the idea and initial version! This script downloads a page with random quotes, filters the html to retrieve just one liners quotes and outputs the first one. Just barely under the required 255 chars :) Improvment: You can replace the head -1 at the end by: $awk 'length($0)>0 {printf( $0 "\n%%\n" )}' > bash_quotes.txt which will separate the quotes with a "%" and place it in the file. and then: $strfile bash_quotes.txt which will make the file ready for the fortune command and then you can: $fortune bash_quotes.txt which will give you a random quote from those in the downloaded file. I download a file periodically and then use the fortune in .bashrc so I see a funny quote every time I open a terminal.

lists files and folders in a folder
lists files and folders in a folder with summary.

See all the commits for which searchstring appear in the git diff

website recursive offline mirror with wget
website recursive offline mirror with wget

Multi line grep using sed and specifying open/close tags
Working with log files that contains variable length messages wrapped between open and close tags it may be useful to filter the messages upon a keyword. This works fine with GNU sed version 4.2 or higher, so pay attention to some unix distros (solaris, hp-ux, etc.). Linux should be ok.

Simple example of the trap command

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