Recently I read the book Signaling PHP by Cal Evans. It's a short book, yet very affordable and it learned me a couple of things. First of all it explains about how you can "capture" a Ctrl+C on your long-running command and do some necessary cleanup work before actually terminating the application. In the appendix it also mentioned the interesting concept of a PID file. [...] In Appendix A of "Signaling PHP", Cal writes about a way to extend a Symfony command to automatically create such a PID file before executing its task, and to delete this file afterwards.
Mattias shares what he calls a "hack" to make it happen globally - using the eventing system built into the Symfony Console functionality and the "console.command" event. He creates a bundle to help with the reading/writing of the PID file and shows how to implement it as a part of the event handling. He does point out one problem with this method (that the "input" object isn't available) so he works around it with the "ArgvInput" component and some manual handling to grab the PID file location provided.