From mboxrd@z Thu Jan  1 00:00:00 1970
From: mascheck@in-ulm.de (Sven Mascheck)
Date: Sun, 14 Aug 2011 15:12:18 +0200
Subject: [TUHS] /usr/bin on V7?
In-Reply-To: <20110813132429.GF27179@lisa.in-ulm.de>
References: <CAGGBd_o=zbtbaJ6x+3ksRVik8EG+hnfjAr9P-4=rBYmqooVHVg@mail.gmail.com>
	<20110813132429.GF27179@lisa.in-ulm.de>
Message-ID: <20110814131218.GG27179@lisa.in-ulm.de>

Sven Mascheck wrote:

> see "Setting Up Unix" in the 7th ed man, vol2b:
> 
> "The system as distributed has all of the binaries in /bin.  Most of
>  them should be moved to /usr/bin, leaving only the ones required for
>  system maintenance (such as icheck, dcheck, cc, ed, restor, etc.)
>  and the most heavily used in /bin.  This will speed things up a bit
>  if you have only one disk, and also free up space on the root file
>  system for temporary files."


- Some are certainly required in /bin because /usr/bin
  might be on a separate disk.  So this certainly includes
  all important diagnostic and repair tools.
  (And keep in mind that pwd, echo and test were not built
   into the 7th ed Bourne shell, yet.)

But which binaries "could" be moved to /usr/bin then?

Out of curiosity I had a look for other (strict) criteria
apart from that you certainly always want to have the
diagnostic+repair tools available in case of problems.

- Some commands are strictly required in /bin because of
  hardcoded exec() paths:  getty(8) execs to /bin/login,
  mv(1) requires /bin/cp,
	
  while other commands interestingly try to exec in both
  directories, rm(1) (-r) does so with "rmdir", tar(1) with
  "mkdir", bc(1) with "dc", and refer(1) with "sort".

  find(1) requires "pwd", but uses popen().

- the absolute minimum in /bin to boot is actually
	sh

  (because mount is in /etc),
  For going multiuser you also need the hardcoded
	login

  And for getting all diagnostic messages (e.g. /etc/rc)
  when going multiuser - with a separate /usr disk -
  you need
	echo, cat, rm, date

- If you don't want to mess around with temporary copies of
  binaries, you need especially for mv :)
	cp

- Searching the commands code for hardcoded paths also yields
	newgrp, as, cc, ld, pwd, 
 

BTW, the System III distribution had these in /bin, AFAIK,

  acctcom   chmod  diff     find  ln      nm      rm     strip  touch
  adb       chown  dirname  grep  ls      nohup   rmail  stty   true
  ar        cmp    du       kas   mail    od      rmdir  STTY   tty
  as        cp     echo     kasb  make    passwd  rsh    su     uname
  basename  cpio   ed       kill  mesg    pdp11   sed    sum    vax
  bs        crypt  env      kun   mkdir   pr      sh     sync   wc
  cat       date   expr     kunb  mv      ps      size   tail   who
  cc        dd     false    ld    newgrp  pwd     sleep  tee    write
  chgrp     df     file     line  nice    red     sort   time


I agree they knew better than me anyway.
So I guess just the above,
minus the SysIII-only commands,
plus the 7thEd-only commands
might be just right for /bin, and that's

  ar   chgrp  date    echo   icheck  mkdir   ps      sh     tail
  as   chmod  dc      ed     kill    mv      pwd     size   test
  at   chown  dcheck  false  ld      ncheck  restor  sleep  touch
  bc   clri   dd      file   ln      newgrp  rm      sort   true
  cat  cmp    df      find   login   od      rmdir   stty   tty
  cc   cp     du      grep   ls      passwd  sed     su