Re: set -m && bash -c "/bin/foo" works but bash -m -c "/bin/foo" doesn't

[Chet Ramey]

On 10/9/22 3:50 PM, Britton Kerin wrote:
> The man page says the options available to set are also usable from
> the command line.
>
> I wanted to run a backgroup script in a new process group from vim and
> print the PGID.
> I ended up with the following:
>
>       :echo system('set -m && bash -c '."'".'((/bin/foo &) && eval
> "echo -n \$\$")'."'")
>
> I thought it would be nicer to use bash -m but it doesn't work (simple example):
>
>       :echo system('bash -m -c "echo foo"')

It works for me from a terminal:

$ ../bash-5.2-patched/bash -m -c '/bin/echo foo'
foo

and in a pipeline:

$ echo abcde | ../bash-5.2-patched/bash -m -c '/bin/cat' | /bin/cat
abcde

> says:
>
>       bash: cannot set terminal process group (31921): Inappropriate
> ioctl for device
>       bash: no job control in this shell
>
> So it seems bash -m and set -m are not equivalent in this context at least.

You get that message when bash doesn't have a controlling terminal or isn't
in the terminal's foreground process group, when job control isn't
possible.

You might try

bash -c 'set -m ; rest of command string'

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/