using winmerge with git diff - replaces unix style null files with a newly created empty windows temp file

winmerge.sh

#!/bin/sh
# using winmerge with git
# replaces unix style null files with a newly created empty windows temp file

file1=$1
if [ "$file1" == '/dev/null' ] || [ "$file1" == '\\.\nul' ] || [ ! -e "$file1" ]
    then 
       file1="/tmp/gitnull"
       `echo "">$file1`
fi
file2=$2
if [ "$file2" == '/dev/null' ] || [ "$file2" == '\\.\nul' ] || [ ! -e "$file2" ]
    then 
       file2="/tmp/gitnull"
       `echo "">$file2`
fi
echo diff : $1 -- $2
"C:\Program files (x86)\WinMerge\WinMergeU.exe" -e -ub -dl "Base" -dr "Mine" "$file1" "$file2"

Goes in C:\Program Files\Git\bin