10

Is it possible to run a command

  • with parameters first of which starts with - (dash) e.g. /usr/bin/echo -n foo
  • as different user and group, for example apache:apache
  • using command su
  • when login shell is set to /sbin/nologin ?

I tried:

  • su -s "/usr/bin/echo" -g apache apache -n foo
    • fails with su: invalid option -- 'n'. It looks like first argument may not start with dash.
  • su -c "/usr/bin/echo -n foo" -g apache apache
    • fails with nologin: invalid option -- 'c'. It looks like -c can't be used if login shell is /sbin/nologin

3 Answers 3

24
su -s /bin/bash -c "/usr/bin/echo -n foo" -g apache apache
  • -s /bin/bash overrides nologin and allows to interpret value of -c option
  • -c "/usr/bin/echo -n foo" allows to avoid using dash-starting first argument
1
  • 2
    su in CentOS 6 doesn't support -g <group> option. This option is supported in CentOS 7 and 8.
    – czerny
    Feb 19, 2020 at 18:28
21

sudo to the rescue!

sudo -u <user> -g <group> -- echo -n foo
4

If the user's login shell is set to /sbin/nologin then the user can't login and su - generally won't work.

But there is the su -m option to preserve the current user's environment and login shell:

su -m <user> -c "<command>"

For example:

su -m apache -c "echo hello; id"

Prints:

hello
uid=33(apache) gid=33(apache) groups=33(apache)

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