Why does my su start in background?

Question

When I use su - fred the job is immediately moved to the background. Then, if I use fg it works normally:

wally@Machine:~$ su - fred
Password:

[1]+  Stopped                 su - fred
wally@Machine:~$ fg
su - fred
fred@Machine:~$

Why did it start in the background?

Output of type -a su (run as wally):

su is /usr/bin/su
su is /bin/su

Output of jobs -l (run as wally):

[1]+  9187 Stopped (signal)        su - fred

fred's startup file (.profile and .bashrc were deleted):

.bash_profile

exec env /bin/bash

I found a related question here.

Do you get the same behaviour if you reverse the roles of fred and wally? — Kusalananda, Jan 15 '20 at 19:22
@Kusalananda Does not do it if the roles are reversed. If fred does su - wally then it starts right away. — wally, Jan 15 '20 at 19:32

score 2 · Accepted Answer · answered Jan 15 '20 at 20:18

2

That happens because bash runs the startup files with job control disabled.

Add set -m at the beginning of your ~/.bash_profile.

1 Answers1