in reply to Is this the best regex?

Perhaps this will work better for you: 

#!/usr/bin/perl
use warnings;
use strict;

open my $PIPE, '-|', 'system_profiler SPApplicationsDataType 2> /dev/n
+ull' or die "Cannot open pipe from 'system_profiler' $!";

my ( $i, $p );
while ( <$PIPE> ) {
    $i += /\A\s{4}\S.*:\Z/;
    $p += /\A\s+Kind: PowerPC\Z/;
    }

close $PIPE or warn $! ? "Error closing 'system_profiler' pipe: $!"
                       : "Exit status $? from 'system_profiler'";

print "$i applications, $p PowerPC applications\n\n";

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Re^2: Is this the best regex?
by Anonymous Monk on Sep 09, 2009 at 04:51 UTC

    Yes -- better!

    It is faster and seems easier to understand. I changed it to:

    #!/usr/bin/perl
use warnings;
use strict;

open my $PIPE, '-|', 'system_profiler SPApplicationsDataType 2> /dev/n
+ull' or die "Cannot open pipe from 'system_profiler' $!";

my ( $i, $p, @apps );

while ( <$PIPE> ) {
    $apps[$i] .= $_;
    $i += /\A\s{4}\S.*:\Z/;
    $p += /\A\s+Kind: PowerPC\Z/;
    }

close $PIPE or warn $! ? "Error closing 'system_profiler' pipe: $!"
                       : "Exit status $? from 'system_profiler'";
                       
foreach (@apps) {
    print if /Kind: PowerPC/s;
    }

print "$i applications, $p PowerPC applications\n\n";

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    Question: is there a difference between /\A\s{4}\S.*:\Z/ and /^\s{4}\S.*:$/?
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