You can also use: $ TZ=CST date -d "Sun Mar 3 18:05:17 UTC 2013" Sun Mar 3 18:05:17 CST 2013 which doesn't invoke a subshell. env vars can always be prepen

You can also use: $ TZ=CST date -d "Sun Mar 3 18:05:17 UTC 2013" Sun Mar 3 18:05:17 CST 2013 which doesn't invoke a subshell. env vars can always be prepended to the executable name for use with just that program (not sure if that's bash only, though).