In Unix, a background process executes independently of the
shell, leaving the terminal free for other work. To run a
process in the background, include an
&
(an ampersand) at the end of the command you use to run the
job. Following are some examples:
- To run the
count
program, which will display the process identification number of the job, enter: count & - To check the status of your job, enter: ps
- To bring a background process to the foreground, enter: fg
- If you have more than one job suspended in the background, enter:
fg %#
Replace
#
with the job number, as shown in the first column of the output of thejobs
command.
- You can kill a background process by entering:
kill PID
Replace
PID
with the process ID of the job. If that fails, enter the following:
kill -KILL PID - To determine a job's PID, enter: jobs -l
- If you are using
sh
,ksh
,bash
, orzsh
, you may prevent background processes from sending error messages to the terminal. Redirect the output to/dev/null
using the following syntax: count 2> /dev/null &
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