Curly braces on the command line

You can do some really interesting and time saving things using curly braces on the bash command line. Essentially, curly braces with a list of things separated by commas means run this command once for each item in the list.

This is best illustrated by a number of examples.

Create a complex folder hierarchy

mkdir -p folder/{1, 2, 3}/{a, b, c}

This creates this folder hierarchy:

folder/
     1/
          a/
          b/
     2/
          a/
          b/
     3/
          a/
          b/

Rename files in a hierarchy

This renames foo/bar/baz/1 to foo/bar/baz/2

mv foo/bar/baz/{1,2} 

Rename variation

This renames /foo/bar/baz/1 to foo/bar/tweedle/2

mv foo/bar/{baz/1, tweedle/2} 

Shortcut for adding extensions

This renames file to file1.backup

mv file1{.,backup}

Add extensions with wildcard matching

This will find files containing the word “banana” and slap an extension on them. This is an interesting case in that {,.bak} means add an extension.

find . -name "banana*" -exec mv \{\}{,.bak} \; 

List files wi…