I'm reading "Network Programming with Perl" by Lincoln Stein, and I've
come across a snippet of code I'mnot quite following:
open (WHOFH, "who |") or die "Can't open who: $!";
While (<WHOFH>) {
next unless /^(\S+)/;
$who{$1}++;
}
It's the 'next' line I'm unclear on. I know that results: parse the
first field from each output line of the 'who' command, but I'm
wondering why this might have been done in this way. It seems to me
that the 'next' line states "get the next record unless the current
one startes with a non-whitespace character".
The UNIX 'who' command output lines always start with non-whitespace
characters, as far as I can see. It seems just as sensible to leave
this line out. Does anyone know additional value to doing this?
Also, the '$who{$1}++' lines has the same effect here as "awk '{ print
$1 }'", and leads me to believe that $2, $3, etc. also exist, but that
doesn't seem to be the case as I've tried printing those variables.
How does the '$1' work in this case?
Thanks
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
http://learn.perl.org/
