Re: Using @ARGV

You have several problems. You are supplying two arguments on the command line so the size of @ARGV is going to be 2.

You would be better off checking to see if @ARGV contains anything and continuing from there.

You are opening the file handle FILE, then reading from STDIN, so you probably are not getting what you expect.

You should never use the captured variables from a regex without checking to see if the match succeded.

use warnings; #<-- also a good idea, especially if you are just starti
+ng perl programming
use strict;

die "Specify a file path\n" unless @ARGV;

open my $fh, shift or die "Cannot open file: $!\n";

while (<$fh>) {
    if (/(\S+)\s+\S+\s+(\S+)\s+(.*)/){ #testing regex and tags
        print "$1, $2, $3\n"; #testing printing
    }
}
close $fh;
print "Done!\n";
[download]

Then leave 'open' out of the command line.

myperlscript.pl "C:/path/to/file/on_windows_pc/file.txt"
[download]

Comment on Re: Using @ARGV Select or Download Code

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Re^2: Using @ARGV by Joost (Canon) on Dec 03, 2005 at 18:29 UTC
Just to clarify this line from thundergnat's post: `open my $fh, shift or die "Cannot open file: $!\n";` [download] shift(), when used outside a subroutine shifts the first element off @ARGV. Another way of accessing the first element would be: `open my $fh, $ARGV[0] or die "Cannot open file: $!\n";` [download] See also perldata, perlvar and shift "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l] [select]
Re^3: Using @ARGV by merlyn (Sage) on Dec 03, 2005 at 18:50 UTC
I'm confused here. Why even open any file at all? Let Perl do it: `while (<>) { .... }` [download] This construct pulls filenames from the `@ARGV` array, automatically. -- Randal L. Schwartz, Perl hacker Be sure to read my standard disclaimer if this is a reply.	[reply] [d/l]
Re^4: Using @ARGV by revdiablo (Prior) on Dec 03, 2005 at 21:50 UTC
This construct pulls filenames from the @ARGV array, automatically. It also introduces some potential security risks if used wantonly, as described in Dangerous diamonds!. These risks are frequently acceptible, and I'm sure you're already aware of them, but I feel it's something worth mention for the benefit of others. :-) Update: thought it might be good to mention the original code uses two-arg open anyway, so switching to `<>` doesn't add any security risks that weren't already there. Another update: quick note about merlyn's reply. I wasn't really "that concerned", which is what I was trying to say when I wrote "these risks are frequently accept[a]ble." Maybe that wasn't very clear.	[reply] [d/l]
Re^5: Using @ARGV by merlyn (Sage) on Dec 04, 2005 at 01:36 UTC
Re^4: Using @ARGV by Joost (Canon) on Dec 04, 2005 at 03:56 UTC
I'm confused here. Why even open any file at all? It's all a matter of documentation, IMO. Yes, perls <> construct is perfectly suited for the "unix way", and it's my personal preference, but it isn't exactly clear for "newbies". In this particular instance, I chose clarity over usability. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply]