T47 Dec 24, 2025 2 min read

Background process

A process running without being the active foreground job of a terminal, often with different I/O and signal behavior.

Definition

A background process is a process that is not the active foreground job in a terminal session.

This can mean:

  • it was started with & or moved to the background via job control
  • it has no controlling terminal because it is running under a supervisor

Why it behaves differently

Background processes often have different behavior around:

  • input and output (stdin may be closed or not connected to a terminal)
  • signals from the terminal (job control signals)
  • lifetime (it might die when the terminal session ends unless supervised)