gistfile1.pl

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


# NOTE This assumes the space aren't tabs and the columns are aligned

my $input = '
SCGR  SC  DEV            DEV1           NUMDEV  DCP  STATE  REASON
1      0                                 31      1
SCGR  SC  DEV            DEV1           NUMDEV  DCP  STATE  REASON
2      0                                 31      1
';

my @input_lines = split /\n/, $input;


foreach my $line (@input_lines) {
    next unless $line;
    my $dev = substr($line, 10, 15);
    $dev =~ s/\s*//g;
    unless ($dev) {
        $line =~ s/(..........)(.....)/$1UNDEF/;
    }
    print $line."\n";

}