Run system command as user

ruby-talk
1

I'm in need of running a system command as another user than the user
that is executing the ruby script. Is this possible? Can I execute
su (and somehow supply the correct password), then run the command?

2

Here is a naive version using the built-in pty extension (*nix only,
but since you mention su, I assume that's not a problem)...

require "pty"
require "expect"

cmd = "sleep 1; sudo -u someuser ls 2>&1"
PTY.spawn(cmd) { | stdin, stdout, pid |
  stdin.expect(/Password:|/) { | result, pass |
    stdout.write("secret_password\n") if pass
  }
  puts stdin.read
}

Regardsm
Jordan

···

On Nov 30, 7:56 pm, Trey <treyb...@gmail.com> wrote:

I'm in need of running a system command as another user than the user
that is executing the ruby script. Is this possible? Can I execute
su (and somehow supply the correct password), then run the command?

3

Depending on how much control you have over the system and what's
available, you might be able to configure sudo to allow your script to
run the command as a different user without a password. If it's
available and you're able to configure sudo on the system (or have
someone do it for you), check the sudoers man page for info on the
NOPASSWD tag.

···

On Nov 30, 7:56 pm, Trey <treyb...@gmail.com> wrote:

I'm in need of running a system command as another user than the user
that is executing the ruby script. Is this possible? Can I execute
su (and somehow supply the correct password), then run the command?

4

> I'm in need of running a system command as another user than the user
> that is executing the ruby script. Is this possible? Can I execute
> su (and somehow supply the correct password), then run the command?

Here is a naive version using the built-in pty extension (*nix only,
but since you mention su, I assume that's not a problem)...

require "pty"
require "expect"

cmd = "sleep 1; sudo -u someuser ls 2>&1"
PTY.spawn(cmd) { | stdin, stdout, pid |
  stdin.expect(/Password:|/) { | result, pass |
    stdout.write("secret_password\n") if pass
  }
  puts stdin.read

}

Regardsm
Jordan

Oops...

    stdout.write("secret_password\n") if pass

    stdout.write("secret_password\n") if pass == "Password:"

···

On Dec 1, 2:41 am, MonkeeSage <MonkeeS...@gmail.com> wrote:

On Nov 30, 7:56 pm, Trey <treyb...@gmail.com> wrote:

5

Good grief. Third time's a charm (maybe)...

require "pty"
require "expect"

PTY.spawn("sleep 1; sudo -u root ls 2>&1") { | stdin, stdout, pid |
  begin
    stdin.expect("Password:") {
      stdout.write("secret_password\n")
      puts stdin.read.lstrip
    }
  rescue Errno::EIO
    # don't care
  end
}

Sorry about that! Was confusing live code with the version I meant to
post (twice!). I was trying to do fancy stuff and detect when the
password was catched already by sudo, but never got that working.

Regards,
Jordan

···

On Dec 1, 2:52 am, MonkeeSage <MonkeeS...@gmail.com> wrote:

On Dec 1, 2:41 am, MonkeeSage <MonkeeS...@gmail.com> wrote:

> On Nov 30, 7:56 pm, Trey <treyb...@gmail.com> wrote:

> > I'm in need of running a system command as another user than the user
> > that is executing the ruby script. Is this possible? Can I execute
> > su (and somehow supply the correct password), then run the command?

> Here is a naive version using the built-in pty extension (*nix only,
> but since you mention su, I assume that's not a problem)...

> require "pty"
> require "expect"

> cmd = "sleep 1; sudo -u someuser ls 2>&1"
> PTY.spawn(cmd) { | stdin, stdout, pid |
> stdin.expect(/Password:|/) { | result, pass |
> stdout.write("secret_password\n") if pass
> }
> puts stdin.read

> }

> Regardsm
> Jordan

Oops...

> stdout.write("secret_password\n") if pass

    stdout.write("secret_password\n") if pass == "Password:"

6

Sweet. It works. Thanks Jordan

···

On Dec 1, 2:18 am, MonkeeSage <MonkeeS...@gmail.com> wrote:

On Dec 1, 2:52 am, MonkeeSage <MonkeeS...@gmail.com> wrote:

> On Dec 1, 2:41 am, MonkeeSage <MonkeeS...@gmail.com> wrote:

> > On Nov 30, 7:56 pm, Trey <treyb...@gmail.com> wrote:

> > > I'm in need of running a system command as another user than the user
> > > that is executing the ruby script. Is this possible? Can I execute
> > > su (and somehow supply the correct password), then run the command?

> > Here is a naive version using the built-in pty extension (*nix only,
> > but since you mention su, I assume that's not a problem)...

> > require "pty"
> > require "expect"

> > cmd = "sleep 1; sudo -u someuser ls 2>&1"
> > PTY.spawn(cmd) { | stdin, stdout, pid |
> > stdin.expect(/Password:|/) { | result, pass |
> > stdout.write("secret_password\n") if pass
> > }
> > puts stdin.read

> > }

> > Regardsm
> > Jordan

> Oops...

> > stdout.write("secret_password\n") if pass

> stdout.write("secret_password\n") if pass == "Password:"

Good grief. Third time's a charm (maybe)...

require "pty"
require "expect"

PTY.spawn("sleep 1; sudo -u root ls 2>&1") { | stdin, stdout, pid |
  begin
    stdin.expect("Password:") {
      stdout.write("secret_password\n")
      puts stdin.read.lstrip
    }
  rescue Errno::EIO
    # don't care
  end

}

Sorry about that! Was confusing live code with the version I meant to
post (twice!). I was trying to do fancy stuff and detect when the
password was catched already by sudo, but never got that working.

Regards,
Jordan