IT 244: Introduction to Linux/Unix

IT 244: Introduction to Linux/Unix
Class 13 Exercise

Copy bother.sh to your ex13 directory

cp  ~ghoffman/course_files/it244_files/bother.sh  .

Run bother.sh and watch it work
```
./bother.sh
```
Stop this program
```
Control  C
```
Run this program again, but this time in the background
```
./bother.sh  &
```
The number in brackets is the job number. The second number is the process number of the first process in the job.
Run jobs
```
jobs
```
jobs shows you the job number of all running jobs, their status, and the command line that created the job.
Run ps
```
ps
```
bother.sh is a simple script containing a loop that never ends. Inside the loop, it sleeps for 5 seconds and then prints something. When bother.sh calls sleep, it initiates a subprocess, which you see beneath bother.sh in the listing.

Bring bother.sh to the foreground
```
fg
```
You don't have to supply a job number because there is only background job.
Suspend this job
```
Control  Z
```
Run jobs
```
jobs
```
The job still exists, but it is suspended.
Run ps
```
ps
```
Both bother.sh and it's sleep subprocess are still there.
Send the job to the background
```
bg
```
Again, since there is no other job, you do not have to supply a job number as an argument.
Run jobs again
```
jobs
```
The job is now in the background and has resumed running.

Run jobs to see the job number
```
jobs
```
Use the job number to kill the job
```
kill  %JOB_NUMBER
```
JOB_NUMBER is the number that the jobs command showed you.
Run jobs to see what happened
```
jobs
```
The job has been terminated.
Run bother.sh in the background one more time
```
./bother.sh  &
```
Run ps to get the process number for bother.sh
```
ps
```
Use this process number to kill the job
```
kill  PROCESS_ID
```
PROCESS_ID is the process ID of bother.sh.
Run jobs to see what happened
```
jobs
```
The job has been terminated.
Run ps to see your running processes
```
ps
```
bother.sh and its subprocess are gone.