Loops In Bash

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BashTricks. I always forget how to do this, and I'm sick of looking it up for that once every two months when I need it.

 for arg in list
 do
  command...
 done

Don't feel like you have to string this all together on one line when you're doing it in an interactive shell. Just hit enter after each line.

To steal an example:

 for planet in "Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto"
 do
   echo $planet
 done

Note that list can be the output of a given program - just use backticks, like so:

 for doc in `ls *.doc`
 do
   file $doc
 done

A real world example:

 for release in `ls`
 do
   iconv -f iso-8859-1 -t utf-8 ./$release ../converted/$release.html
 done

You probably should use globs instead, though:

 for release in *
 do
   foo ./$release
 done