Yes, lvlamb, but this is LINUX documentation. You know, "Our documentation doesn't have to be accurate, we'll just call you stupid when it doesn't work for you."
As far as I know, the basic sh does not have the environment variable, $UID for user ID, same as id -u.
If I run a script on Linux and use the variable $UID it works. (This is with a script that begins #!/bin/sh.)
If I do it on a FreeBSD box, using sh, it won't work.
HOWEVER--the Debian people did put together a dash shell, which one can use to test true portability.
Now, you would expect that something on the LDP would be correct. It should be. It's official and all that stuff.
And there you have my biggest complaint about Linux. As the quote says that the two things out of Berkeley were BSD and LSD, one would think that it's after reading BSD docs that you would shout, "Were they on drugs??". However, it's the sort of thing I often say after reading a Linux doc.
(Oh, and our DrJ of these forums also came out of Berkeley, so that's three good things.)
Hopefully, you realize that I'm not fighting with you over this--your only error is to assume that Linux documentation isn't an oxymoron.
Ok, yes, I'm bitter, I've spent all morning looking to find out some stupid little thing that should have been in the docs.
I feel SOO much better now.