Use GNU Parallel: short, easy to read, and will run one job per core.

Convert some SVG files into PNG using ImageMagick's convert command.

Run the conversions in parallel to save time.

This is safer than robinro's forkbomb approach :-)

xargs runs four processes at a time -P4

Convert a camelCase string into snake_case.

To complement senorpedro's command.

You want bash to keep running the command until it is successful (until the exit code is 0). Give a dummy command, which sets the exit code to 1 then keep running your command until it exits cleanly

This snippet will produce an alpha-numeric 16 character password

Deletes files in the current directory or its subdirectories that match "regexp" but handle directories, newlines, spaces, and other funky characters better than the original #13315. Also uses grep's "-q" to be quiet and quit at the first match, making this much faster. No need for awk either.

Grep can search files and directories recursively. Using the -Z option and xargs -0 you can get all results on one line with escaped spaces, suitable for other commands like rm.

After this command you can review doit.sh file before executing it.

If it looks good, execute: `. doit.sh`

Saves opening another console terminal (eg. CTRL+ALT+F[n]) or opening another remote terminal.

Ctrl+Z pauses the current task and pushed it to the background, leaving you with a command prompt for those "Oh crap I forgot to change xyz before I ran that and it'll take forever if I Ctrl+C and start again..." situations. Typing 'fg' (shorthand for foreground, that's how I remember it) will resume the paused task.

You have an external USB drive or key.

Apply this command (using the file path of anything on your device) and it will simulate the unplug of this device.

If you just want the port, just type :

echo $(sudo lshw -businfo | grep -B 1 -m 1 $(df "/path/to/file" | tail -1 | awk '{print $1}' | cut -c 6-8) | head -n 1 | awk '{print $1}' | cut -c 5- | tr ":" "-")

Reads n lines from stdin and puts the contents in a variable. Yes, I know the read command and its options, but find this logical even for one line.

Prints out an ascii chart using builtin bash! Then formats using cat -t and column.

The best part is:

From: http://www.askapache.com/linux/ascii-codes-and-reference.html

Today, I needed to reboot a Windoze machine on another continent which had no shutdown or restart options via "Start" in the remote desktop (the only options available were: "Logoff, Disconnect, or Lock").

Fortunately, I found how to shutdown and restart from the command line.

hgrep()

{

if [[ ${#} -eq 0 ]]

then

printf "usage:\nhgrep [--nonum | -N | -n | --all-nonum | -an | -na] STRING\n"

return 1

fi

while [[ ${#} -gt 0 ]]

do

case ${1} in

--nonum | -N | -n | --all-nonum | -an | -na)

builtin history | sed 's/^[[:blank:]]\+[[:digit:]]\{1,5\}[[:blank:]]\{2\}//' | grep -iE "(${*:2})"

break

;;

*)

builtin history | grep -iE "(${*})"

break

;;

esac

done

}

'hgrep -n' helps in using full grep support, e.g. search for _beginning_ of specific commands,

see example output

The 'rename' command with the first argument as "'s/\.//'" and the second argument as "" will remove the specified extension from the filenames.

By defining a function "hg" as shown here, it saves me typing "history | grep" every time I need to search my shell history because now I only have to type "hg".

A nifty time saver :-)

You can also add the "hg" function definition to your .bashrc so it is defined each time you login.

Waits for all pings to complete and returns ip with mac address

--dry-run will only show you which files would be otherwise synced with rsync.

-z is for compressio

-v vervose

-a "as is" - permissions, ownership etc.

Finds all nfo files without the filename movie.nfo and deletes them.

find . -maxdepth 1 -iname ".*" | awk 'NR >= 2'

Can be used to list only dotfiles without . nor ..