And don't tell me there isn't one bit of difference between null and space,
because that's exactly how much difference there is.  :-)

Because . doesn't match \n.  [\0-\377] is the most efficient way to match
everything currently.  Maybe \e should match everything.  And \E would
of course match nothing.   :-)

Although the Perl Slogan is There's More Than One Way to Do It, I hesitate
to make 10 ways to do something.  :-)

The only disadvantage I see is that it would force everyone to get Perl.
Horrors.  :-)

That's not short.  This is short:         :-)
#!/usr/bin/perl
@n=('pwu','grg');sub n{local($n)=eval"get$n[$_[1]]id(\$_[0])";$n&&"($n)";}sub nm
{$a-$b;}@gr=split(' ',$();$g=shift(@gr);$\="\n";print"uid=$<",&n($<)," gid=",$g,
&n($(,1),(" euid=$>".&n($>))x($<!=$>),(" egid=".$)+0 .&n($),1))x($(!=$)),
(" groups=".join(',',sort nm grep(($_.=&n($_,1))||1,@gr)))x($#gr>=0);

Though I'll admit readability suffers slightly...
Larry

: I find this a nice feature but it is not according to the documentation.
: Or is it a BUG?

Let's call it an accidental feature.  :-)