I love how deadpan the bug report is:

    Actual results:
    All files are deleted on the machine.

    Expected results:
    Squid is restarted.

[0] https://github.com/valvesoftware/steam-for-linux/issues/3671

I would bet on the issue being in the init script itself rather than squid. (I'm assuming squid doesn't run as root by default in rhel) If that's true then it's another point for more sane process managers (upstart/supervisord/systemd/...)

Agreed, I should've elaborated. All it takes is something like this in the init script without checking if the variable is empty:

    rm -rf "$STEAMROOT/"*

And this is why it is important to write something like

    set -eu

or check the variable before using it, like any other programming language:

[[ "$VAR" ]] && rm -rf "$VAR/*"

I think most of these issues stem from the fact that most developers that write shell scripts don't actually understand what they're doing, treating the script as a necessary annoyance rather than a component of the software.

If anyone understands shell scripts, it would be people writing init scripts at Red Hat :)

Anyways, that is not anything like other programming languages. Checking in that way is error prone and not really an improvement (nor equivalent to set -o).

  [[ "$DAEMON_PATH" ]] && rm -rf "$DEAMON_PATH/*"

In other programming languages, if an identifier is mis-typed things will blow up. E.g., in ruby if I write:

  daemon_path=1; if daemon_path; puts deamon_path; end

These issues do not always stem from bad developers. Bash's defaults are not safe in many ways and saying "people should just check the variable" isn't helpful here.