Even more so, the worst coworker I ever had once wrote a script that accepted neither, and (when run) would default to trying to process data (and deleting it whether or not it was fully handled) _in production_. The first time we ever ran it (unsuspectingly) was after he'd left for Facebook. Good riddance.
One place I worked had very explicit rules about that that would be drilled into new recruits. Besides --help, running without argument was also required to print the help.
I was told that this rule came about when they "discovered", presumably at nontrivial cost, a disk imaging tool that would default to unconditionally mirroring the first hard disk onto the second.
Oooo, not failing on unknown arguments is evil. It's almost guaranteed at that point that what you're about to do is not what the user expects to happen.
GNU cat is on the naughty list, supporting --help but not -h. less is the same (and is not part of GNU).
edit Looks like the GNU echo, sort, and uniq programs are the same. GNU has an official policy endorsing --help but not -h. [0]
Also related: --version should print the version numbers (and perhaps build details) of the software, and immediately terminate.
-v lacks the (at least somewhat) universal meaning of -h, though. Some commands, such as curl, use -v as shorthand for --verbose rather than --version, but all commands should support --version.
I believe Java HotSpot used to use -version, supporting neither -v nor --version. Now it supports both --version and -version, but not -v.
To be honest, it should, or if you feel like your program is very simple then you could do what feh(1) does and simply print "see man $PROGRAM". Running -h or --help on a program which spits out an "unknown argument" error is one of my pet peeves.
