When you execute a unix shell-script or command that takes a long time, you can run it as a background job.
In this article, let us review how to execute a job in the background, bring a job to the foreground, view all background jobs, and kill a background job.
1. Executing a background job
Appending an ampersand ( & ) to the command runs the job in the background.
For example, when you execute a find command that might take a lot time to execute, you can put it in the background as shown below. Following example finds all the files under root file system that changed within the last 24 hours.
# find / -ctime -1 > /tmp/changed-file-list.txt &
2. Sending the current foreground job to the background using CTRL-Z and bg command
You can send an already running foreground job to background as explained below:
- Press ‘CTRL+Z’ which will suspend the current foreground job.
- Execute bg to make that command to execute in background.
For example, if you’ve forgot to execute a job in a background, you don’t need to kill the current job and start a new background job. Instead, suspend the current job and put it in the background as shown below.
# find / -ctime -1 > /tmp/changed-file-list.txt # [CTRL-Z] [2]+ Stopped find / -ctime -1 > /tmp/changed-file-list.txt # bg
3. View all the background jobs using jobs command
You can list out the background jobs with the command jobs. Sample output of jobs command is
# jobs [1] Running bash download-file.sh & [2]- Running evolution & [3]+ Done nautilus .
4. Taking a job from the background to the foreground using fg command
You can bring a background job to the foreground using fg command. When executed without arguments, it will take the most recent background job to the foreground.
# fg
If you have multiple background ground jobs, and would want to bring a certain job to the foreground, execute jobs command which will show the job id and command.
In the following example, fg %1 will bring the job#1 (i.e download-file.sh) to the foreground.
# jobs [1] Running bash download-file.sh & [2]- Running evolution & [3]+ Done nautilus . # fg %1
5. Kill a specific background job using kill %
If you want to kill a specific background job use, kill %job-number. For example, to kill the job 2 use
# kill %2
To kill a foreground jobs, use one of the methods specified in our earlier article 4 Ways to Kill a Process — kill, killall, pkill, xkill.
My name is Ramesh Natarajan. I will be posting instruction guides, how-to, troubleshooting tips and tricks on Linux, database, hardware, security and web. My focus is to write articles that will either teach you or help you resolve a problem. Read more about
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Nice!!!
very usefull !
Thanks, exactly what I am looking for.
How to determine if a process running background or foreground?
Especially, from inside: i.e. script going to use ‘read var <temr' from a terminal, but it is bad idea, if script running background; so, need to skipp reading.
thank you. Useful tricks ;D
after executing ctrl+z and bg command on a running process, will the process resume from the point where it stopped?
Excellent
how would you run the .sh script without bringing it to the foreground first?
Gud one..
Came to know to put a foreground running process to background in between…
Awesome!
How can I suspend a background job?
Proved to be useful for me.
Thank You.
Super
Thanks
Thanks. this is really helpfull.
Nice
This is EXACTLY what I was looking for, thanks! 🙂
Big thanks to you
Is there a way to make [ctrl-z] not automatically stop a job, but instead just move it to the background?
Awesome and useful!
Very useful and easy to understand
Thanks , very userful
Thanks, quite useful.
Excellent!!!
seems screen command not available ..
could you provide real time example for screen command