#!/bin/sh
#
# right - change the pathname to an execbasename in a script's "shebang" header
#
# $Id$

me=`basename $0`

Erro()
{
  echo "$me: error: $@" 1>&2
}

if [ $# -lt 2 ]
then
  Erro "you must supply an execbasename and one or more scripts"
  exit 1
fi

execbasename=$1
shift

if type "$execbasename"
then
  execfullname=`type "$execbasename" | awk '{print $NF}'`
else
  Erro "no executable '$execbasename' found"
  exit 2
fi

if [ ! -x $execfullname ]
then
  Erro "executable $execfullname is not executable"
  exit 3
fi

scriptfound=

echo the executable is $execbasename, full name $execfullname

for f in "$@"
do
  if [ ! -f $f ]
  then
    Erro "skipping $f, not a plain file"
  elif perl -lpe 'exit !m:^#!.*'"$execbasename"'(\s|$):' "$f"
  then
    perl -0pi.un$me -e 's:^#!.*'"$execbasename"'(\s|$):#!'"$execfullname"'$1:' "$f"
    scriptfound=1
  fi
done

if [ X = X"$scriptfound" ]
then
  echo $0: none of the arguments is a $execbasename script 1>&2; exit 2
fi

exit 0