pgrep, pkill, kill, and jobs

1. As the root user, create a job running in the background of your current terminal. Execute this following script for that program process to be created.

[root@localhost]# (while true; do echo -n "My program" >> ~/output.file; done) &

2. View the current jobs running in the background of your terminal.

[root@localhost ~]# jobs
[1]-  Running   ( while true; do< echo -n "My program" >> ~/output.file; done ) &

3. Stop the process from running without killing the process using the kill command.

[root@localhost]# kill -SIGSTOP %1 (%1 is the job number, if the job was 2 it would be %2)

4. View the stopped jobs in the background.

[root@localhost ~]# jobs

[1]+  Stopped     ( while true; do echo -n "My program" >> ~/output.file; done ) &

[root@localhost ~]#  

5. Start the process again using the kill command.

[root@localhost]# kill -SIGCONT %1

6. Kill the process without allowing any blocking of the kill command.

[root@localhost]# kill -SIGKILL %1

Exercise 2:

1. Download and install the httpd service.

[root@localhost]# yum install httpd

2. Start the httpd service (or ensure that it is running).

[root@localhost]# systemctl start httpd

3. As the root user, grep for all processes that are running as the root user and display the process names.

[root@localhost]# pgrep -u root -l

4. As the user "user", start the "vi" program at the terminal.

[user@localhost]# vi

5. As the root user, in your second terminal window grep for all processes running under the user "user".

[root@localhost ~]# pgrep -u anthony -l vi
3690 dconf-service
3694 vim

6. As the root user, grep for the httpd process.

[root@localhost]# pgrep httpd

7. As the root user, kill all of the user "user"'s processes and boot user from the system.

[root@localhost ~]# w
 14:15:59 up 20:55,  4 users,  load average: 0.00, 0.01, 0.05
USER     TTY        LOGIN@   IDLE   JCPU   PCPU WHAT
user pts/0     Mon22    2:58m  0.05s  0.05s bash
[root@localhost ]# pkill -t pts/0 

This will kill every process started from the user's terminal but it will not boot the user. Now find all running processes left which should either be bash or ssh.

[root@localhost]# pgrep -u user
[root@localhost]# pgrep kill bash 
or 
[root@localhost]# pgrep kill ssh