Bash — Processes

Listing processes

ps aux               # All processes
ps -ef               # Full format
ps aux | grep name   # Find process
top                  # Interactive monitor
htop                 # Better monitor

Background processes

#!/bin/bash

# Run in background
long_command &

# See background jobs
jobs

# Bring to foreground
fg %1

# Suspend and background
# Ctrl+Z
bg %1

Signals

#!/bin/bash

# Common signals
kill -TERM PID    # Terminate (default)
kill -INT PID     # Interrupt (Ctrl+C)
kill -KILL PID    # Force kill (Ctrl+\)
kill -HUP PID     # Hangup (reload config)

# Trap signals
trap 'echo "Caught SIGINT"' INT
trap 'echo "Cleaning up"' EXIT

Process substitution

#!/bin/bash

diff <(ls dir1) <(ls dir2)
while read line; do
    echo "$line"
done < <(command)

Mini Practice

Write Bash code that:

1. Lists and finds processes
2. Runs a command in the background
3. Uses trap for cleanup
4. Uses process substitution

Up Next

In the next lesson, you'll learn about Environment Variables — configuring your shell.