Jobs: bg, fg & nohup

Run commands in the background, bring them forward, and keep them alive after logout.

Syntaxcommand & jobs fg %1 nohup command &

A long-running command normally ties up your terminal. Job control lets you push it into the background and get your prompt back.

Background and foreground

  • End a command with & to start it in the background.
  • Press Ctrl+Z to pause the current command.
  • bg resumes the paused job in the background; fg brings it back to the foreground.
  • jobs lists the background jobs of this shell.

Surviving logout

Background jobs still stop when you close the terminal. Wrap a command in nohup ... & so it keeps running after you log out.

Example

Example · bash
# Start a long job in the background
./backup.sh &
# [1] 2043

# See background jobs
jobs
# [1]+  Running   ./backup.sh &

# Bring job 1 back to the foreground
fg %1

# Keep running after you log out
nohup ./server.sh &

When to use it

  • A developer runs a long build with 'make &' to background it, then continues editing source files in the same terminal.
  • A sysadmin uses 'Ctrl+Z' then 'bg' to background a running 'vim' session, run a quick check, then 'fg' to return to editing.
  • A DevOps engineer uses 'nohup ./deploy.sh &' to keep a deployment running after closing their SSH session.

More examples

Background and list jobs

Shows how & runs a command in the background and jobs lists all current shell background jobs with their IDs.

Example · bash
# Start a command in the background with &
sleep 60 &
# [1] 7890

# List all background jobs
jobs
# [1]+  Running    sleep 60 &

Suspend, background, and foreground

Demonstrates the full Ctrl+Z / bg / fg cycle for moving a process between foreground and background.

Example · bash
# Start a process
vim file.txt

# Press Ctrl+Z to suspend it
# [1]+  Stopped    vim file.txt

# Resume it in the background
bg %1

# Bring it back to the foreground
fg %1

Survive session close with nohup

Uses nohup to make a background job immune to SIGHUP so it persists after the SSH session ends.

Example · bash
# Run job immune to hangup signal
nohup ./long_backup.sh > backup.log 2>&1 &
# [1] 8001

# Job keeps running after SSH disconnect
# Check output later
tail -f backup.log

Related

linux ps toplinux systemctl

Discussion

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