This is called brace expansion: http://wiki.bash-hackers.org/syntax/expansion/brace http://wiki.bash-hackers.org/syntax/expansion/brace Very useful stuff. E.g.

This is called brace expansion: http://wiki.bash-hackers.org/syntax/expansion/brace http://wiki.bash-hackers.org/syntax/expansion/brace Very useful stuff. E.g. mv nginx.conf{,.old}