Weird file in /usr/bin ?!?

Hi all.
By accident I found a file on my kubuntu laptop in /usr/bin with the name [
Info:
/usr/bin$ file '['
[: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.15, stripped

When I logon to my WD network drive there are two :) but these are softlinks:

[ -> ../../bin/busybox
[[ -> ../../bin/busybox

Maybe it is all on Google, but searching on [ is a bit problematic.
Thanks ! Dan

Hmm. Found it,
should have --h'd it. It is an alternate (or link to) the test command. Seems to have it's origin in the beginning of bash.