#! /usr/bin/ksh

export LC_ALL=C
export PATH=/usr/bin:/bin

cfg=/etc/vac.cfg
targbin=/usr/vac/bin/xlc
sysbin=/usr/bin
targman=/usr/vac/exe/default_msg/vac.help
extman=.1

# Determine the stanza names from the config file
stanzas=`sed -ne '/^DEFLT:/ d' -e '/^[a-zA-Z0-9_]*:/ { s/:.*$//
p
}' -- "$cfg"` || {
  print -u2 "Cannot determine compiler invocation names from $cfg."
  exit 1
}

[[ -n $stanzas ]] || {
  print -u2 "No compiler invocation names were found in $cfg."
  exit 1
}

# replace(name,link-target)
function replace {
  [[ -e $1 ]] && {
    [[ -e $saved/${1##*/} ]] && {
      if cmp -s -- "$1" "$2"; then
        print -u1 -- "$1 has already been replaced."
	return 0
      elif cmp -s -- "$1" "$saved/${1##*/}"; then
        # degenerate case, /usr/bin is a dup of saved copy
	rm -f -- "$1" || {
	  return 1
        }
      else
        print -u2 "ERROR: $saved/${1##*/} already exists."
	print -u2 "       $1 can not be replaced."
	return 1
      fi
    }
    print -u1 "Replacing $1"
    mv -- "$1" "$saved/${1##*/}" || {
      print -u2 "ERROR: Problems saving $1, skipping."
      return 1
    }
  }
  ln -s -- "$2" "$1" || {
    return 1
  }
  return 0
}

fail=0
for cmd in $stanzas; do
  replace $sysbin/$cmd        $targbin || fail=1
done
exit $fail