I made absolutely no change except for running password <user> as root. After logging back in as <user> and running, for example, su pkg install rsync mtr I am returned the following su([39208]): BAD SU <user> to pkg on /dev/tty0
su: sorry

running id shows that i my user is still in usergroup wheel.

also: running just plain su with no command returns a root shell with no problems.

the /etc/passwd : here's the line regarding my user

<username redacted>: *:1002:0:curnc:/home/<user>:/usr/local/bin/bash

what is curnc? i dont remember ever associating my user with such a reference.

I have no idea how to troubleshoot this.

  • 1
    su -c 'pkg install rsync mtr' – Tom Yan Dec 2 '19 at 5:59

what is curnc?

man 5 passwd says the fifth field is "user name or comment field". It's designed to contain human-readable information about the user. It's not important to the issue.

su is not sudo. The first operand (see this) is interpreted as user you want to become.

su [options] [username]

The su command is used to become another user during a login session. Invoked without a username, su defaults to becoming the superuser. […]

Additional arguments may be provided after the username, in which case they are supplied to the users login shell. In particular, an argument of -c will cause the next argument to be treated as a command by most command interpreters. The command will be executed by the shell specified in /etc/passwd for the target user.


Your command

su pkg install rsync mtr

means "change user to pkg and run /login/shell/of/this/user install rsync mtr". Probably no user named pkg exists, hence BAD SU <user> to pkg. Note <user> to pkg corresponds with the fact the command tried to change <user> to pkg.

This is not what you wanted in the first place. I think you wanted

su -c 'pkg install rsync mtr'

(credits to this comment, although it lacks explanation).

With sudo the syntax could be more like what you tried:

sudo pkg install rsync mtr

The most visible difference is sudo asks for the current user's password (unless configured otherwise); su asks for the target user's password. More about differences: here.

  • in my five years using linux, i've never needed to do this. why now that i've changed my password? is it a coincidence / or is uranus in retrograde in the house of aquarius? – Andrew Dec 2 '19 at 18:53
  • this doesn't work. when i use su -c 'cmd' i am asked for the root password, not my user password. secondly, after giving the root password i am returned the error 'only root may use sudo -c' – Andrew Dec 2 '19 at 18:56
  • my user is in wheel, and has permission to run su with its user password, but is not root. – Andrew Dec 2 '19 at 18:57
  • @Andrew (1) Have never needed to do what? (2) With su -c 'cmd' the target user is root, so you've been asked for the the root password. (3) Where did sudo come from ("only root may use sudo -c")? Was it in cmd? (4) Groups like wheel may matter to sudo, su doesn't care. (5) What command exactly do you want to run? Is it pkg install rsync mtr? – Kamil Maciorowski Dec 2 '19 at 19:06
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    @Andrew If su used to work like sudo then this was wrong. The current behavior is standard. You should not try to restore the old behavior. Frankly I suspect it was sudo pkg install rsync from the very beginning and you just confused su with sudo. – Kamil Maciorowski Dec 4 '19 at 9:05

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