Hrmmm . . . I copied only the relevant code from my script, above:

C:\chas_sandbox\columns-by-name>
copy con ARGVtest.pl
#!/usr/bin/perl -WCD

use strict;
use warnings;
use Data::Dumper;

$\ = $/;
my $debug = 1;

#array of fields to display
my @processFields = ('Caption','ParentProcessId','ProcessId','CommandL
+ine');

#ARGV processing
my $searchfor = $ARGV[0] ? join(' ',@ARGV) : die("I need a process to 
+look for."
);
^Z
        1 file(s) copied.

C:\chas_sandbox\columns-by-name>
notepad ARGVtest.pl
[download]

and changed it a little (in notepad, above) and tested it:

C:\chas_sandbox\columns-by-name>
type ARGVtest.pl
#!/usr/bin/perl -WCD

use strict;
use warnings;
use Data::Dumper;

$\ = $/;
my $debug = 1;

#array of fields to display
my @processFields = ('Caption','ParentProcessId','ProcessId','CommandL
+ine');

#ARGV processing
my $searchfor = $#ARGV ? join(' ',@ARGV) : die("I need a process to lo
+ok for.");
#               ^^^^^^ change here

C:\chas_sandbox\columns-by-name>
ARGVtest.pl
I need a process to look for. at C:\chas_sandbox\columns-by-name\ARGVt
+est.pl lin
e 14.

C:\chas_sandbox\columns-by-name>
ARGVtest.pl chas
I need a process to look for. at C:\chas_sandbox\columns-by-name\ARGVt
+est.pl lin
e 14.
[download]

and added some debug (in notepad again) and tested again:

C:\chas_sandbox\columns-by-name>
type ARGVtest.pl
#!/usr/bin/perl -WCD

use strict;
use warnings;
use Data::Dumper;

$\ = $/;
my $debug = 1;

#array of fields to display
my @processFields = ('Caption','ParentProcessId','ProcessId','CommandL
+ine');

#ARGV processing
print Dumper(\@ARGV);
print $#ARGV;
my $searchfor = $#ARGV ? join(' ',@ARGV) : die("I need a process to lo
+ok for.");


C:\chas_sandbox\columns-by-name>
ARGVtest.pl
$VAR1 = [
          ''
        ];

0
I need a process to look for. at C:\chas_sandbox\columns-by-name\ARGVt
+est.pl lin
e 16.

C:\chas_sandbox\columns-by-name>
ARGVtest.pl chas
$VAR1 = [
          ' chas'
        ];

0
I need a process to look for. at C:\chas_sandbox\columns-by-name\ARGVt
+est.pl lin
e 16.
[download]

. . . and it sure looks like $#ARGV is 0 either way. I totally trust your experience, so I conclude that either my test is wrong or my conclusions are. Does the she-bang line arguments mess this up or something?

You have:

my $searchfor = $#ARGV ? join(' ',@ARGV) : die("I need a process to lo
+ok for.");
[download]

• If there are no arg, $#ARGV is -1, $#ARGV is true, $search_for = join(' ', ()).
• If there is one arg, $#ARGV is 0, $#ARGV is false, die("I need a process to look for.").
• If there is two arg, $#ARGV is 1, $#ARGV is true, $search_for = join(' ', $ARGV[0], $ARGV[1]).
• ...

You want

my $searchfor = $#ARGV >= 0 ? join(' ',@ARGV) : die("I need a process 
+to look for.");
[download]

Or better yet:

my $searchfor = @ARGV ? join(' ',@ARGV) : die("I need a process to loo
+k for.");
[download]

I don't understand why that's one one line. It doesn't save anything. I just adds complexity.

@ARGV or die("I need a process to look for.");
my $searchfor = join(' ',@ARGV);
[download]

What about the print $#ARGV; statement that printed 0 where you seem to have predicted it should print -1?

I take your point about the difference between $#ARGV (highest index) and @ARGV in scalar context (number of elements) and agree I should have used the number of elements. That's a mental block for me and has caused me problems in the past.

I also take your point about complexity. I think I was looking for something parallel in style to open() || die(); for consistency.

---

#my sig used to say 'I humbly seek wisdom. '. Now it says:
use strict;
use warnings;
I humbly seek wisdom.

Thanks and ++ for the tip about :std or :locale. It's working in place as is, so I'll file this away for the next time I'm working on it. Again, it's a one-off script, but this is a good place to document the caveats for others who might be researching similar things.

Quick note, it's not :std or :locale. They work in conjunction.