Fix error and dependency checking

bin/gvm

@@ -20,7 +20,7 @@ fi
 
 $GVM_ROOT/scripts/gvm-check
 if [[ "$?" != "0" ]]; then
-	display_error "Missing requirements."
+	display_fatal "Missing requirements."
 fi
 
 if [[ $command == "version" ]]; then
@@ -30,7 +30,7 @@ else
 		shift
 		$GVM_ROOT/scripts/$command $@
 	elif [[ -n $command ]]; then
-		display_error "Unrecognized command line argument: '$command'"
+		display_fatal "Unrecognized command line argument: '$command'"
 	else
 		echo "Usage: gvm [command]
 

scripts/function/display_warning

@@ -9,4 +9,5 @@ display_warning() {
 	else
 		echo "$1"
 	fi
+	return 1
 }

scripts/gvm-check

@@ -2,36 +2,36 @@
 . $GVM_ROOT/scripts/functions
 
 # Check for hg
-[ -z `which hg` ] &&
+which hg &> /dev/null ||
 	display_warning "Could not find mercurial
 
   linux: apt-get install mercurial
   mac:   brew install mercurial
-" && exit 1
+" || exit 1
 # Check for ar
-[ -z `which ar` ] &&
+which ar &> /dev/null ||
 	display_warning "Could not find binutils
 
   linux: apt-get install binutils
-" && exit 1
+" || exit 1
 # Check for bison
-[ -z `which bison` ] &&
+which bison &> /dev/null ||
 	display_warning "Could not find bison
 
   linux: apt-get install bison
-" && exit 1
+" || exit 1
 # Check for gcc
-[ -z `which gcc` ] &&
+which gcc &> /dev/null ||
 	display_warning "Could not find gcc
 
   linux: apt-get install gcc
-" && exit 1
+" || exit 1
 # Check for make
-[ -z `which make` ] &&
+which make &> /dev/null ||
 	display_warning "Could not find make
 
   linux: apt-get install make
-" && exit 1
+" || exit 1
 
 # All good!
 exit 0