Linux · Process Management

An unmount fails because a directory is "in use" but you can't see any obvious program touching it. Which command reveals the culprit, and what non-obvious thing counts as "using" it?

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More in Process Management

On Linux, what single file attribute distinguishes a runnable program from an ordinary data file, and why does that make file extensions irrelevant for execution?

A Windows user asks where the .exe files live on a Linux box. What is the accurate answer, including the one real exception?

You just compiled a binary in your current directory and typing its name gives "command not found". Why, and what is the fix?

From a desktop terminal, what does xdg-open do that plain execution does not, and what is its portable-looking alias on some distros?

In a terminal, what is the difference between a foreground and a background job, and how do you move an already-running foreground command into the background without killing it?

Plain ps in a terminal shows only a handful of processes on a busy graphical system. Why, and what invocation lists everything?

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