bash golf problem

threshold.sh

#!/bin/bash
# Input:
#     output this 6
#     do not output this 5
#
# Output (and a non-zero exit code):
#     output this 6

THRESHOLD=5

cat test_file |
  ruby -ne "puts \$_ if \$_.split(' ').last.to_i > \"${THRESHOLD}\".to_i" | \
  ruby -e 'out = STDIN.read; puts out; exit(1) if out.length > 0'