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On Sun, Feb 19, 2006 at 04:05:23PM -0500, Jeff Abrahamson said: > On Sun, Feb 19, 2006 at 03:58:45PM -0500, Kyle R. Burton wrote: > > On 2/19/06, Jeff Abrahamson <jeff@purple.com> wrote: > > > > > In a bash script I want to compare two files (one or both of which may > > > not exist) and take a certain action if they *both* exist and are > > > identical. > > > > > Can you just: > > > > if cmp -s "$f" "$dir2/b"; then > > echo "same" > > else > > echo "not same" > > fi > > > If one doesn't exist it returns 2. That's in your else clause, then. roughly: if cmp -s "$f" "$dir2/b"; then echo same do_stuff_for_same else case "$?" in 1) echo differ do_stuff_for_different ;; 2) echo missing do_stuff_for_missing ;; esac fi Probably prettier ways of doing it, but you get the idea - if the if returns true, then the files differ because cmp exited 0. Otherwise, you'll have to examine $? to see what it's value is. You can't, as far as I know, do the examination of return status in line as you can in other languages ( the `if ( ( ret = do_something ) == 0 )' syntax you're looking for). If you figure out a way to do it that I'm unaware of, please pass it on. HTH, -- -------------------------------------------------------------------------- | Stephen Gran | BOFH excuse #73: Daemons did it | | steve@lobefin.net | | | http://www.lobefin.net/~steve | | --------------------------------------------------------------------------
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