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The $[...] block in bash and zsh will let you do math.
This is the same as using $((...)), which also works in ksh. Of course, this is a simple, dumb wrapper and doesn't allow floating-point.
unsets variables used by the one-liner
sets up the IFS bash variable to not be affected by whitespace and disables extra glob expansion
uses read to slurp the results of the find command into an array
selects an element of the array at random to be passed as an argument to mplayer
This command deletes all files in all subfolders if their name or path contains "deleteme".
To dry-run the command without actually deleting files run:
find . | grep deleteme | while read line; do echo rm $line; done
or, to process a single directory:
for f in *; do mv $f `echo $f |tr '[:upper:]' '[:lower:]'`; done
or, for a single directory:
for f in *.c; do mv $f "`basename $f .c`".C; done
Modify the script for your username and password, and save it as a script. Run the script, and enjoy ./tweet
Add @mail.com each line of a list
Imagemagick library is used. If image format is not JPEG, the "quality" option should not be issued.
customizable context searches - if you know sed, this is a basis for more complex context control than grep --context offers
just for fun