#!/bin/bash
# UNIX/WORLD, IV:11


PATH=/bin:/usr/bin
script=$(basename $0)
case $# in

	0)
		vim
		exit 0
		;;

	1)
		if [ ! -f "$1" ]
			then
				vim "$1"
				exit 0
			fi
		if [ ! -r "$1" -o ! -w "$1" ]
			then
				echo "$script: check permissions on $1" 1>&2
				exit 1
			else
				editfile=$1
			fi
		if [ ! -w "." ]
			then
				echo "$script: backup cannot be " \
					"created in the working directory" 1>&2
				exit 1
			fi
		;;
	*)
		echo "Usage: $script [file-to-edit]" 1>&2
		exit 1
		;;
esac
tempfile=/tmp/$$.$script
cp $editfile $tempfile
if vim $editfile
	then
		mv $tempfile bak.$(basename $editfile)
		echo "$script: backup file created"
    else
		mv $tempfile editerr
		echo "$script: edit error--copy of " \
			"original file is in editerr" 1>&2
fi