0x05-processes_and_signals

Processes and signals

In this project, I learned about handling process ID's and signals in Bash with ps, pgrep, pkill, pkill, exit, and trap.

Tasks 📃

• 0. What is my PID

  • 0-what-is-my-pid: Bash script that displays its own PID.

• 1. List your processes

  • 1-list_your_processes: Bash script that displays a list of currently running processes.
  • Shows all processes for all users, including those not featuring a TTY.
  • Processes are displayed in a user-oriented hierarchy.

• 2. Show your Bash PID

  • 2-show_your_bash_pid: Bash script that displays lines containing the bash keyword based on the script defined in 1-list_your_processes.

• 3. Show your Bash PID made easy

  • 3-show_your_bash_pid_made_easy: Bash script that displays the PID along with the process name of processes who name contains the word bash.

• 4. To infinity and beyond

  • 4-to_infinity_and_beyond: Bash script that displays To infinity and beyond indefinitely with a sleep 2 in between each iteration.

• 5. Don't stop me now!

  • 5-dont_stop_me_now: Bash script that kills the 4-to_infinity_and_beyond process using kill.

• 6. Stop me if you can

  • 6-stop_me_if_you_can: Bash script that kills the 4-to_infinity_and_beyond process using pkill.

• 7. Highlander

  • 7-highlander: Bash script that displays To infinity and beyond indefinitely with a sleep 2 in between each iteration.
  • Displays I am invincible!!! upon receiving a SIGTERM signal.

• 8. Beheaded process

  • 8-beheaded_process: Bash script that kills the process 7-highlander.

• 9. Process and PID file

  • 100-process_and_pid_file: Bash script that creates the file /var/run/myscript.pid containing its PID and displays To infinity and beyond indefinitely.
  • Displays I hate the kill command upon receiving a SIGTERM signal.
  • Displays Y U no love me?! upon receiving a SIGINT signal.
  • Deletes the file /var/run/myscript.pid and terminates itself upon receiving the SIGQUIT or SIGTERM signal.

• 10. Manage my process

  • manage_my_process: Bash script that writes I am alive! to the file /tmp/my_process indefinitely.
    • Sleeps two seconds in between each write.
  • 101-manage_my_process: Bash script that manages the manage_my_process script.
  • When passed the argument start:
    • Starts manage_my_process.
    • Creates a file containing its PID in /var/run/my_process.pid.
    • Displays manage_my_process started.
  • When passed the argument stop:
    • Stops manage_my_process.
    • Deletes the file /var/run/my_process.pid.
    • Displays manage_my_process stopped.
  • When passed the argument restart:
    • Stops manage_my_process.
    • Deletes the file /var/run/my_process.pid.
    • Starts manage_my_process.
    • Creates a file containing its PID in /var/run/my_process.pid.
    • Displays manage_my_process started.
  • Otherwise, displays Usage: manage_my_process {start|stop|restart}.

• 11. Zombie

  • 102-zombie.c: C program that creates five zombie processes.
  • For every zombie created, displays Zombie process created, PID: <ZOMBIE_PID>.