Prerequisites check: Test for non-zero value

Also, use alternate syntax for which-test and exit with non-zero exit
code for git-test as well.

gitwatch.sh

@@ -65,16 +65,14 @@ shift $((OPTIND-1)) # Shift the input arguments, so that the input file (last ar
 # Check for both git and inotifywait and generate an error
 # if either don't exist or you cannot run them
 
-which git &>/dev/null
-if [ $? -eq 1 ]; then
+if ! which git &>/dev/null; then
     echo >&2 "Git not found and it is required to use this script."
     exit 1
 
 fi
-which inotifywait &>/dev/null
-if [ $? -eq 1 ]; then
+if ! which inotifywait &>/dev/null; then
     echo >&2 "inotifywait not found and it is required to use this script."
-    exit
+    exit 1
 fi
 
 # These two strings are used to construct the commit comment