UNIX rename script, DOS Style

[abeath08]

HI,
as part of my college work, I have to create a UNIX command which can rename in the style of the DOS rename. I have the basic code working, which will rename the files. But i cant seem to get the file extension, rename bit sorted. I think it might be my regex but not sure, any help would be good. Here is the code i have so far:

#!/bin/sh
#
# - A DOS STYLE RENAME
#
case $# in
0)			echo "Usage: dosRename file [ ... ] target"
			exit
			;;
#2)			echo "dosRename: $file: Can't have anything after target"
#			exit
#			;;
'..')		echo "dosRename: $file: Can't have more than one dot"
			exit
			;;
'**')  		echo "dosRename: $file: Can't have more than one asterisk"
			exit
			;;
#[!-f])  	echo "dosRename: $file: Doesn't exist"
#			exit
#			;;
6)  		echo "dosRename: $file: Must have a dot"
			exit
			;;
7)			echo "dosRename: No target"
			exit
			;;
*)			for file
			do
				case $file in
				[A-Za-z0-9]*\.\*) 	filePart=name
									;;
				\*\.[A-Za-z0-9]*) 	filePart=etx
									;;
				esac
			done
			endFile=$file
			fileName=`echo $endFile | sed -e 's/\.\*//'`
			extension=`echo $endFile | sed -e 's/\*\./\./'`
			while [ $# -ne 1  ]
			do
					case $filePart in
						'name')     result=`echo $1 | sed -e "s/[A-Za-z0-9]*\.\(.*[A-Za-z0-9]*\)/$fileName\.\1/"`
									mv $1 $result
									;;
						'ext')    	result=`echo $1 |sed -e "s/\.[A-Za-z0-9]*/$extension/"`
									mv $1 $result
									;;
					esac
				 shift 1
			done
			 ;;
esac

ps. I am not aloud to use python as we have not covered it in this section of the course

 

[abeath08]

its ok i had a spelling mistake, all sorted thanks