I don't think diff produces output which can be parsed easily for your purposes. It's possible to solve your problem by iterating over the files in the two directories and running diff on them, using the return value from diff instead (and throwing the diff output away).
The code to do this is a bit long, but here it is:
DIR1=./one # set as required
DIR2=./two # set as required
# Process any files in $DIR1 only, or in both $DIR1 and $DIR2
find $DIR1 -type f -print0 | while read -d $'\0' -r file1; do
relative_path=${file1#${DIR1}/};
file2="$DIR2/$relative_path"
if [[ ! -f "$file2" ]]; then
echo "'$relative_path' in '$DIR1' only"
# Do more stuff here
elif diff -q "$file1" "$file2" >/dev/null; then
echo "'$relative_path' same in '$DIR1' and '$DIR2'"
# Do more stuff here
else
echo "'$relative_path' different between '$DIR1' and '$DIR2'"
# Do more stuff here
fi
done
# Process files in $DIR2 only
find $DIR2 -type f -print0 | while read -d $'\0' -r file2; do
relative_path=${file2#${DIR2}/};
file1="$DIR1/$relative_path"
if [[ ! -f "$file2" ]]; then
echo "'$relative_path' in '$DIR2 only'"
# Do more stuff here
fi
done
This code leverages some tricks to safely handle files which contain spaces, which would be very difficult to get working by parsing diff output. You can find more details on that topic here.
Of course this doesn't do anything regarding files which have the same contents but different names or are located in different directories.
I tested by populating two test directories as follows:
echo "dir one only" > "$DIR1/dir one only.txt"
echo "dir two only" > "$DIR2/dir two only.txt"
echo "in both, same" > $DIR1/"in both, same.txt"
echo "in both, same" > $DIR2/"in both, same.txt"
echo "in both, and different" > $DIR1/"in both, different.txt"
echo "in both, but different" > $DIR2/"in both, different.txt"
My output was:
'dir one only.txt' in './one' only
'in both, different.txt' different between './one' and './two'
'in both, same.txt' same in './one' and './two'