Thanks for the 'use warnings;' suggestion.

Keep in mind the subject here is maintainence - where small changes with minimal impact to production is the rule and the work is often done by programmers with incomplete knowledge and no patience for explanations. For maintenance you want KISS, not TMTOWTDI.

I'm no big fan of bash but at least bash gets the common case right here without any special settings. For example, if I use -eq instead of == and write

  #!/bin/bash                                                                     
  x=`cat FOO 2>/dev/null`
  if [ $x -eq 'bar' ]; then
    echo baz
  fi

as you imply, bash won't be silent. It will say

  bash-3.2$ ./example.sh 
  ./example.sh: line 3: [: bar: integer expression expected