use strict;
use warnings;

my $result = <<'EOT';
transaction 1234567; promote; 2014/08/01 10:22:37 ; user: john
  # Performing a "promote" on file.
  /./abc/desf/test.pl 138699/1 (138700/1) 

transaction 4578643; promote; 2014/08/01 10:22:37 ; user: sam
  /./abc/desf/test.pl 138699/1 (138700/1) 
EOT

while ($result =~ /transaction (\d+).*user:\s*(\S+)\s*(?:#\s*(.*))?/g) {
            my ($transaction, $user, $comment) = ($1, $2, $3);
            printf "%-12s %-10s %s\n", $1, $2, $3//'';
}