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

my $in = <DATA>;
my @fields =
        # Remove leading & trailing space from each list element
        map { s/^\s+//; s/\s+$//; $_ }
        # Split input string into fields at '|'
        split /\|/, $in;

print join('|',@fields), "\n";
__DATA__
abcd |abcd|abcd   |      abcd       | abcd|