`export PS1='value'` does not propagate to (Korn) subshells for root?

Please co开发者_运维百科nsider the following /root/.profile:

export PS1=value1
export x=value2

How come the login shell shows the expected prompt (and $x as value2), while the subshells keep showing $x as value2 but $PS1 as '#'? Just in case, I'm trying this under OpenBSD.

[Yeah, I know... What on earth am I doing with OpenBSD if I don't know this? Just toying... in an isolated, most definitely non-production VM =).]

---

Because your subshells are sourcing something that's resetting PS1.

To debug this, try ksh -x. If that doesn't help, you could try running ksh in strace or an equivalent system call tracing tool.

---

In case anybody is interested, somebody finally explained this in an OpenBSD mailing list. This behavior is actually expected in OpenBSD, as explained in a comment inside /usr/src/bin/ksh/main.c:

safe_prompt = ksheuid ? "$ " : "# ";
{
    struct tbl *vp = global("PS1");

    /* Set PS1 if it isn't set, or we are root and prompt doesn't
     * contain a # or \$ (only in ksh mode).
     */
    if (!(vp->flag & ISSET) ||
        (!ksheuid && !strchr(str_val(vp), '#') &&
        (Flag(FSH) || !strstr(str_val(vp), "\\$"))))
        /* setstr can't fail here */
        setstr(vp, safe_prompt, KSH_RETURN_ERROR);
}

---

Check the following files for rogue PS1 assignments.

   /etc/profile
          The  system  wide initialization file, executed for login shells.
   $HOME/.profile
          The personal initialization  file,  executed  for  login  shells
          after /etc/profile.
   $HOME/..kshrc
          Default  personal  initialization file, executed for interactive
          shells when ENV is not set.
   /etc/suid_profile
          Alternative initialization file, executed when instead  of  per-
          sonal  initialization  file  when the real and effective user or
          group id do not match.

There may be a typo in that manpage, it probably meant to say: $HOME/.kshrc