Shell job control

Job Control Bash can run jobs in the background or in the foreground. A running Program It is called a process or job. Each process has a process ID, PID. Generally, all programs run on the foreground. You can use Ctrl + D to send a signal to pause the program. A paused process can be run in the background, sent back to the foreground, or terminated.

[Root @ localhost ~] #VI# Open the VI editor and press Ctrl + Z to pause it. [1] + stopped vi [Root @ localhost ~] # Sleep 400 & # Add &, indicating running in the background [2] 5277 [Root @ localhost ~] # Jobs # Display the current job in the background [1] + stopped vi [2]-running sleep 400 & [Root @ localhost ~] # Jobs-l # Display the current job and PID in the background [1] + 5276 stopped vi [2]-5277 running sleep 400 & [Root @ localhost ~] # Jobs % # Display commands recently added to the job table [1] + stopped vi [Root @ localhost ~] # FG % 1 # FG transfers the job with job number 1 to the foreground [Root @ localhost ~] # Kill % 1 # Killing a job with job number 1 VIM: Caught deadly signal term VIM: finished.

 

Job control commands

Command	Description
BG	Start a terminated background job
FG	Transfer background jobs to the foreground
Jobs	List all running jobs
Kill	Sends a kill signal to a specified job
Stop	Suspends a background job.
Stty tostop	When a background job sends an output to a terminal, it is suspended.
Wait [N]	Wait for a specified job and return its exit status. Here N is a PID or job number.
∧ Z (CTRL-Z)	Terminate (suspend) A Job. A prompt appears on the screen.
Parameters of the jobs command	Description
% N	Task No. N
% String	Job name starting with string
%? String	Job name contains string
%	Current job
% +	Current job
%-	The first job of the current job.
-R	List all running jobs
-S	List all pending jobs