MySQL and predictive option handling – beware

MySQL command line utilities have an interesting property – if you only use the prefix of the option or command it will go over the list of available command and if there is only one command with matching prefix it will execute it with no warnings or any kind, otherwise it will report the error. For example mysqladmin e works as there is only one command “extended-status” which starts with “e” mysqladmin f however does not work because there are multiple commands which start with “f”.

This behavior can cause all kings of issues especially if you make a typo. I made one today (thankfully on the test box). MySQL init Scripts use “stop” and “start” commands to start and stop the server while mysqladmin uses “shutdown”. I mixed this while trying to stop Percona Server: