--- a/build/set-version.sh	Tue Oct 18 18:42:13 2016 +0200
+++ b/build/set-version.sh	Wed Oct 19 00:31:18 2016 +0200
@@ -2,8 +2,34 @@
 
 set -e
 
+function usage() {
+    cat <<EOF
+Usage: $0 "x.y.z"
+    "x.y.z": version number, following the semver convention
+EOF
+}
+
+if [ $# -ne 1 ]; then
+    echo "Bad number of parameters"
+    usage >&2
+    exit 1
+fi
+
+if [[ "$1" == "-h" || "$1" == "--help" ]]; then
+    usage
+    exit 0
+fi
+
 version=$1
 
+echo "Version: ${version}"
+
+[[ "${version}" =~ ^[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+$ ]] || {
+    echo "Bad format for version."
+    usage >&2
+    exit 1
+}
+
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 green="\x1B[0;32m" # '\e[1;32m' is too bright for white bg.
 blue="\x1B[1;34m"