It is often remarked that one never knows what one has until it is lost. While I think that most people do believe something along those lines, I suspect that such feelings are normally reserved for the big things in life: security, companionship, et cetra.
Personally, get this feeling every time I log onto a proprietary UNIX machine. Perhaps you recognize the situation: for every one of your clever little shell incantations, the machine responds with a brutally cold, "illegal option." I know that this command worked yesterday!" you say to yourself.
And then it dawns on you. You were on the Linux box yesterday.
These are the times that make us realize just how good we have it. Not only have the fine people at the FSF provided us with tools which are free--as in software--but also tools which are superior with an incredible amount of robustness and functionality.
Case in point: Today I was writing a script for our users to generate public keys for use with ssh (scp). The ssh implementation on Tru64 uses a different key format than OpenSSH. Fine, no big deal. That's not where the problem was.
The problem was with humble little grep. I wanted to capture the name of the key created from the ssh-keygen command. With the GNU version it's easy to pick out a just a matching pattern, rather than the entire line: just use the -o option:
$ grep -o 'pattern'
looking
for a pattern
> pattern
find the pattern in the line
> pattern
many little patterns. find all of the patterns
> pattern
> pattern
On the Tru64 version, there's no such option. In fact, the number of available options (17) falls far short of those made available by the GNU version (41). I'm not going to argue whether all of those options are necessary, but you'll be happy they are there when you need them most.
Luckily perl is installed on this machine, so I was still able to solve the problem:
$ perl -ne '/id_dsa_\d+_[^.]+/ && print $&, qq/\n/'Of course, this solution presents its own difficulties. Namely, you might be writing a script that needs to be maintained by someone that's taken a few Korn Shell classes, yet knows absolutly zero perl. Besides, this is only an example. Sometimes the workaround doesn't come so easily. (Not to mention that perl is under an open source license as well.)
So the moral of the story? Be greatful for what you have: especially fantastic software, provided to you for free by volunteers.
