Add usage.

Change-Id: I6c92771e1217d582e367eaf61d8de1500b2176c1

1 files changed, 40 insertions, 23 deletions

diff --git a/backflip b/backflip
index 4aad6a7..87a6e53 100755
--- a/backflip
+++ b/backflip
@@ -24,29 +24,6 @@ COLOR=true
 TMPDIR=/tmp/$(basename "$0")-$$
 PREFIX=${TMPDIR}/backport
 
-# Arguments
-while getopts "b:r:v:x" options
-do
-  case $options in
-    r ) REF_BRANCH=$OPTARG
-    ;;
-    b ) DEV_BRANCH=$OPTARG
-	STACKED=true
-    ;;
-    v ) VERSION=$OPTARG
-	REF_BRANCH=linaro-local/gcc-${VERSION}-integration-branch
-    ;;
-    x ) INTERACTIVE=false
-        COLOR=false
-    ;;
-  esac
-done
-shift $(($OPTIND - 1))
-
-if [ -z ${DEV_BRANCH+x} ]; then
-  DEV_BRANCH=${REF_BRANCH}
-fi
-
 # Style 
 if $COLOR; then
   NC='\e[0m'
@@ -60,6 +37,11 @@ lines=`perl -E 'say "-" x 80'`
 # ==============================================================================
 # Functions
 # ==============================================================================
+usage() {
+  tool="$(basename "$0")"
+  echo -e "$tool [-v GCC_VERSION] [-r REF_BRANCH] [-b DEV_BRANCH] [-x] REVISION"
+}
+
 print_step() {
   echo -e "${blue}${lines}\n${red}** ${1}\n${blue}${lines}${NC}\n"
 }
@@ -147,6 +129,41 @@ clean() {
   exit $1
 }
 
+# Arguments
+while getopts ":b:r:v:x" options
+do
+  case $options in
+    r ) REF_BRANCH=$OPTARG
+    ;;
+    b ) DEV_BRANCH=$OPTARG
+	STACKED=true
+    ;;
+    v ) VERSION=$OPTARG
+	REF_BRANCH=linaro-local/gcc-${VERSION}-integration-branch
+    ;;
+    x ) INTERACTIVE=false
+        COLOR=false
+    ;;
+    \?) print_info "Option -${bold}$OPTARG${NC} Unsupported."
+        exit 1
+    ;;
+    : ) print_info "Option -${bold}$OPTARG${NC} requires an argument."
+        usage
+        exit 1
+    ;;
+  esac
+done
+
+if [ $# -lt 1 ]; then
+    usage ; exit 1
+fi
+
+shift $(($OPTIND - 1))
+
+if [ -z ${DEV_BRANCH+x} ]; then
+  DEV_BRANCH=${REF_BRANCH}
+fi
+
 # ==============================================================================
 # Checking Configuration
 # ==============================================================================