The hlds_run script hangs when it is supposed to restart the server

[MegaBrutal]

When the server crashes, hlds_run attempts to create a bug report before restarting the server. Instead, it hangs. The reason for this is tries to cat the pidfile in the following lines.

   191				# check to see if a core was dumped
   192				if test -f core ; then
   193					CORE="core"
   194				elif test -f core.`cat $PID_FILE`; then
   195					CORE=core.`cat $PID_FILE`
   196				elif test -f "$HL.core" ; then
   197					CORE="$HL.core"
   198				fi

The problem is that PID_FILE is not always defined (despite the script tries to ensure that). When it is unset, cat ends up being called without arguments so it reads from the standard input, effectively hanging the script. Killing the cat process lets the script advance.

I'd generally suggest to revise the script by modern standards and use shellcheck to uncover potential issues.