Comment by rob74

This may be controversial, but sometimes I feel the biggest mistake is using a shell script in the first place. For example, on servers where you have PHP installed anyway, a PHP CLI script is often an alternative. Say what you will about PHP, but PHP code is much more readable than shell scripts - especially if everyone working on the server is fluent in PHP anyway. Shell scripts do have their niche, but often you find that the scope of a script keeps growing, then soon it becomes cumbersome and makes you wish you would have chosen another alternative from the start...