Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ihnp4!occrsh!occrsh.ATT.COM!rjd
From: rjd@occrsh.ATT.COM
Newsgroups: comp.sys.att
Subject: Re: Non-standard shell and su.
Message-ID: <144800008@occrsh.ATT.COM>
Date: 6 Jan 88 01:56:00 GMT
References: <200@icus.UUCP>
Lines: 25
Nf-ID: #R:icus.UUCP:-20000:occrsh.ATT.COM:144800008:000:1237
Nf-From: occrsh.ATT.COM!rjd    Jan  5 19:56:00 1988


>Another ploy for getting  ksh for root  is to simply  link /bin/ksh on
>top of /bin/sh.  I've been running this way for quite a while  with no
>problems (3.5).  I  do recall  some ancient problems with cron scripts
>breaking and  log  files  growing forever  in the   2.5/3.0 days,  but
>something fixed that.
>
>	Bill Carpenter

  Some problems can occur if the stock Bourne shell is changed.

   I linked /bin/ksh to /bin/sh on a 3B2 model 310 running the stock AT&T
System V factory load 2.0.5 (makes sense, as I am here at the factory).
Actually I just copied over /bin/sh (and saved a copy of sh over in /usr).
Well, suddenly all sorts of things quit working (a suspicion I had, which
was the reason I saved a copy of sh).  The most memorable was that at(1)
bombed.  When at(1) sets up the job file in /usr/spool/cron/atjobs, it
saves the COMPLETE current enviroment of the user.  Well, it just so happens
that some variables were marked "readonly", most notably PPID.  When the
atjob was executed, it nonetheless tried to set PPID (or was it PWD?),
notwithstanding its readonly status.  At the step where it was trying to set
the readonly variable, it bombed.  .....So I moved the original Bourne shell
back to /bin/sh....

Randy