View source for Bg, fg and jobs

bg, fg and jobs are [[process]] related [[commands]] that belong together. bg stands for background and fg stands for foreground.

= Concept =
When you start a [[program]] under Linux, by default the command runs in the foreground. This means the console is reserved for in- and output to and from this program. You do not get a prompt while the program is running. Here is an example for this showing the program xclock being called by the command 
 xclock

[[File:Snapshot-fg-xclock.png]]

This program runs in the foreground, the console is reserved for its in- and output. To run the same program in the background, start it with the ampersand ("&") after the program name:
 xclock &

[[File:Snapshot-bg-xclock.png]]

In this case you can continue to call further [[commands]] on the console.

= Hints =
Maybe you have started a program without the & behind it, and now you want to use console to issue further commands. In this case stop the program using CTRL_Z:
 tweedleburg:~ # xclock
 ^Z
 [1]+  Stopped                 xclock
List it using the command jobs
 tweedleburg:~ # jobs
 [1]+  Stopped                 xclock
And send it to the background using the command bg
 tweedleburg:~ # bg
 [1]+ xclock &
 tweedleburg:~ #
Now it will be as if you had called the command with the & behind it. You will be able to use console for issueing further commands.

= See also =
* [[disown]]
* http://www.lehman.cuny.edu/cgi-bin/man-cgi?jobs+1

[[Category:Concept]]