0x05-processes_and_signals

0x05. Processes and signals

0-what-is-my-pid

Write a Bash script that displays its own PID.

1-list_your_processes

Write a Bash script that displays a list of currently running processes.

Requirements:

• Must show all processes, for all users, including those which might not have a TTY
• Display in a user-oriented format
• Show process hierarchy

2-show_your_bash_pid

Using your previous exercise command, write a Bash script that displays lines containing the bash word, thus allowing you to easily get the PID of your Bash process.

Requirements:

• You cannot use pgrep
• The third line of your script must be # shellcheck disable=SC2009 (for more info about ignoring shellcheck error here)

3-show_your_bash_pid_made_easy

Write a Bash script that displays the PID, along with the process name, of processes whose name contain the word bash.

Requirements:

• You cannot use ps

4-to_infinity_and_beyond

Write a Bash script that displays To infinity and beyond indefinitely.

Requirements:

• In between each iteration of the loop, add a sleep 2

5-dont_stop_me_now

We stopped our 4-to_infinity_and_beyond process using ctrl+c in the previous task, there is actually another way to do this.

Write a Bash script that stops 4-to_infinity_and_beyond process.

Requirements:

• You must use kill

6-stop_me_if_you_can

Write a Bash script that stops 4-to_infinity_and_beyond process.

Requirements:

• You cannot use kill or killall

7-highlander

Write a Bash script that displays:

• To infinity and beyond indefinitely
• With a sleep 2 in between each iteration
• I am invincible!!! when receiving a SIGTERM signal

Make a copy of your 6-stop_me_if_you_can script, name it 67-stop_me_if_you_can, that kills the 7-highlander process instead of the 4-to_infinity_and_beyond one.

8-beheaded_process

Write a Bash script that kills the process 7-highlander.

100-process_and_pid_file

Write a Bash script that:

• Creates the file /var/run/myscript.pid containing its PID
• Displays To infinity and beyond indefinitely
• Displays I hate the kill command when receiving a SIGTERM signal
• Displays Y U no love me?! when receiving a SIGINT signal
• Deletes the file /var/run/myscript.pid and terminates itself when receiving a SIGQUIT or SIGTERM signal

101-manage_my_process, manage_my_process

Write a manage_my_process Bash script that:

• Indefinitely writes I am alive! to the file /tmp/my_process
• In between every I am alive! message, the program should pause for 2 seconds

Write Bash (init) script 101-manage_my_process that manages manage_my_process. (both files need to be pushed to git)

Requirements:

• When passing 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 passing the argument stop:
  • Stops manage_my_process
  • Deletes the file /var/run/my_process.pid
  • Displays manage_my_process stopped
• When passing 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 restarted
• Displays Usage: manage_my_process {start|stop|restart} if any other argument or no argument is passed

102-zombie.c

Write a C program that creates 5 zombie processes.

Requirements:

• For every zombie process created, it displays Zombie process created, PID: ZOMBIE_PID
• Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
• When your code is done creating the parent process and the zombies, use the function below

int infinite_while(void)
{
    while (1)
    {
        sleep(1);
    }
    return (0);
}