Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!samsung!emory!hubcap!ncrcae!ncrlnk!ncrcce!mercer
From: mercer@ncrcce.StPaul.NCR.COM (Dan Mercer)
Newsgroups: comp.unix.wizards
Subject: SYS V Bourne Shell .shrc file
Message-ID: <1792@ncrcce.StPaul.NCR.COM>
Date: 22 Dec 89 00:00:52 GMT
Reply-To: mercer@ncrcce.StPaul.NCR.COM (Dan Mercer)
Organization: NCR Comten, Inc.
Lines: 41
Keywords:

While hacking around trying to include some difficult functionality
for a program I was writing,  I examined /bin/sh with a binary
display program looking for undocumented options.  Instead,  I ran
into the string .shrc.  Intrigued,  I quickly formulated a .shrc file
in my home directory to echo Hello, world!.  After that,  when I forked
to the shell,  I got the message,  providing it was an interactive
shell (if you pipe to the shell,  for instance to unshar a file,  or using
the vi !! command,  it is not invoked).  The .shrc is also invoked
prior to /etc/profile and ~/.profile on login.  Since I use my
.shrc to invoke my shell functions and much of the functionality
that I already do in .profile,  I check for the existence of a
shell environment variable I set in .profile and only execute it
if it already exists.  Of course,  as with .profile,  do not
place any exits in the file.

I am system administer on two boxes,  so I use my prompt to indicate
which box I'm on,  what line,  the depth of my shell nesting,  and
my current working directory.  Really cuts down on the confusion,
since I'm frequently on both boxes simultaneously,  often on
multiple lines (we're testing out Token Ring software connecting
the two boxes,  so I may be kermitted from one box to the other
over a direct asynch line,  the nloginned back to the original
box via Token Ring.

One of the truly wonderful things,  it's invoked under su as well.
I just check to see if PS1 == '# ' (don't forget space),  I reset
my path to something reasonable,  instead of the annoying and
insecure :/etc:/bin:/usr/bin.

I already know this capability does not exist on SUN OS3.5.

Other SYSV users,  let me know if you have it.

Our system consists of two NCR Towers running SYSVR1 and SYSVR2 and
I have confirmed it's existence on another Tower running SYSVR3.2.


-- 

Dan Mercer
Reply-To: mercer@ncrcce.StPaul.NCR.COM (Dan Mercer)