UNIX: Shortcut to create a backup copy of a file

Contributed by barretj July 19, 2005  
Tagged: UNIX

Copy and rename a file in a shorter step than the normal cp file file.bak

If you have a file named foobar and you want to make a backup copy named foobar.bak you could do

cp foobar foobar.bak

but what if the file has a long name, and you have a similarly named file so tab-expansion wont work?

Here’s what you can do instead:

cp foobar{,.bak}

the shell will automagically expand this to cp foobar foobar.bak

note: I tested this in bash and zsh, other shells may or may not work