Or you can skip the whole regex for parsing delimited data. Text::CSV_XS is not just for commas anymore. Text::CSV_XS also has the advantage of dealing with escaped and quoted data.

For brevity, error checking was not added to the code.

use strict;
use warnings;
use Text::CSV_XS;

# Setup a CSV obj to parse the user seperator
my $csv_in  = Text::CSV_XS->new({ sep_char => '^' });

# Setup a CSV obj to handle the output seperator
my $csv_out = Text::CSV_XS->new({ sep_char => '|' });

open(IN,"in_file") or die "$!\n";
my %hash;
while (my $line = <IN>) {
  my $status = $csv_in->parse($line);
  my @cols = $csv_in->fields();
  $hash{$cols[0]} = $cols[1]; # or whatever
}

foreach (keys %hash) {
  my $string = $csv_out->combine($_,$hash{$_});
  print "$string\n";
}
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