perl command line arguments

jluther has asked for the wisdom of the Perl Monks concerning the following question:

When typing a one-liner on the command line, is there a way to use arguments while using the -ne switches. e.g. I want to submit an argument to something like this...


perl -ne 'split(/,/);if ($_[7] eq $arg){$cnt++;}END{print     "There a
+re $arg things in this file\n";}' file_name.txt
[download]

Is there a switch that allows me to pass the argument "$arg" in to this command. This way I don't have to type this command all of the time. Thanks. jluther

Comment on perl command line arguments Download Code

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Re: perl command line arguments by borisz (Canon) on Jun 21, 2004 at 20:32 UTC
Not really a switch, but what about BEGIN? This should work, the first param is the argument. `perl-ne 'BEGIN {$arg = shift} split(/,/);if ($_[7] eq $arg){$cnt++;}EN +D{print "There are $cnt things in this file\n";}' arg file_name.txt` [download] Boris	[reply] [d/l]
Re^2: perl command line arguments by jluther (Novice) on Jul 26, 2004 at 22:15 UTC
Thanks!! I've been on vacation so I am just trying these out. This seems to be the most intuitive. jluther	[reply]
Re: perl command line arguments by itub (Priest) on Jun 22, 2004 at 00:25 UTC
You can try -s: `perl -sne 'split(/,/);if ($_[7] eq $arg){$cnt++;}END{print "There +are $arg things in this file\n";}' -- -arg=something file_name.txt` [download] Note that you need -- to stop perl itself from trying to use -arg as an argument.	[reply] [d/l]
Re: perl command line arguments by Fletch (Bishop) on Jun 21, 2004 at 20:39 UTC
`@ARGV` works just fine in code from `-e`. Update: D'oh, /me glossed completely over the -n part. The first `shift` in the BEGIN block's the way I'd do it. Must be Monday . . .	[reply] [d/l] [select]
Re^2: perl command line arguments by thor (Priest) on Jun 21, 2004 at 23:14 UTC
@ARGV works just fine in code from -e. Yep, it does. However, the meaning is changed under -n. Or at least one has to jump through a hoop (namely a BEGIN block) to get to it before the loop created by -n gets to it. But I'm sure you knew that. See perldoc perlrun for more info. thor	[reply]
Re: perl command line arguments by vladb (Vicar) on Jun 21, 2004 at 20:37 UTC
You could try setting an environment variable and then accessing it in your perl command via the %ENV hash (works in tcsh shell): `setenv arg="ARG"; perl -ne '<your command here>'` [download] Alternatively, you could set the $arg variable at the start of your perl command once: `perl -ne '$arg="ARG";<rest of your command here>'` [download] _____________________ "We've all heard that a million monkeys banging on a million typewriters will eventually reproduce the entire works of Shakespeare. Now, thanks to the Internet, we know this is not true." Robert Wilensky, University of California	[reply] [d/l] [select]
Re: perl command line arguments by Roy Johnson (Monsignor) on Jun 22, 2004 at 00:07 UTC
`perl -F, -ane '$arg\|\|=pop; ++$cnt if $F[7] eq $arg }{ print "There are + $cnt $arg s\n"' filename.txt string` [download] if you're not searching for a single zero. We're not really tightening our belts, it just feels that way because we're getting fatter.	[reply] [d/l]

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