If you have a process ID but aren't sure whether it's valid, you can use the most unlikely of candidates to test it: the kill command. If you don't see any reference to this on the kill(1) man page, ...

Sure, using the Linux command line is optional. But these are commands I depend on every day. See what you think.

It’s a testament to how far Linux has come that users today don’t typically have to use the command line if they don’t want to. Such is the quality of the graphical user interfaces in many modern ...