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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.

grep processes list avoiding the grep itself
Trick to avoid the form: grep process | grep - v grep

Show the disk usage for files pointed by symbolic link in a directory
You also can sum the file usage of all files $ find /usr/lib -maxdepth 1 -type l -print0 | xargs -r0 du -Lch

Force wrap all text to 80 columns in Vim
This is assuming that you're editing some file that has not been wrapped at 80 columns, and you want it to be wrapped. While in Vim, enter ex mode, and set the textwidth to 80 columns: $ :set textwidth=80 Then, press: $ gg to get to the top of the file, and: $ gqG to wrap every line from the top to the bottom of the file at 80 characters. Of course, this will lose any indentation blocks you've setup if typing up some source code, or doing type setting. You can make modifications to this command as needed, as 'gq' is the formatting command you want, then you could send the formatting to a specific line in the file, rather than to the end of the file. $ gq49G Will apply the format from your current cursor location to the 49th row. And so on.

Debug your makefile
Say your dependencies specified in your Makefile (or dates on your source files) is causing 'make' to skip some source-files (that it should not) or on the other other end, if it is causing make to always build some source-files regardless of dates of target, then above command is handy to find out what 'make' thinks of your date v/s target date-wise or what dependencies are in make's view-point. The egrep part removes the extra noise, that you might want to avoid.

Show which programs are listening on TCP ports
Alternative: $ ss -tlpn

list files recursively by size

Update zone file Serial numbers
Will edit *.db files in the same directory with todays date. Useful for doing a mass update to domains on a nameserver, adding spf records, etc. Looks for a string starting with 200 or 201 followed by 7 numbers, and replaces with todays date. This won't overwrite Ip's but i would still do some double checking after running this. Make sure your server's date is correct, otherwise insert your own serial number. $rndc reload should usually follow this command.

Serial console to a Vmware VM
Create a serial console with "socket (named pipe)" of "/tmp/socket", "from:server, to:virtual machine" in vmware player, etc.. gui. Run the above command after you have booted the guest OS (which should also be configured for serial console).

Most Commonly Used Grep Options
This is very helpful to place in a shell startup file and will make grep use those options all the time. This example is nice as it won't show those warning messages, skips devices like fifos and pipes, and ignores case by default.


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