Merge pull request #727 from michaeljones/compare-usage

Print usage message from 'compare'

documentation/compare

@@ -1,14 +1,25 @@
-#!/bin/sh
+#!/bin/sh -e
 
 first=$1
 second=$2
 
-firstdir=comparison/first
-seconddir=comparison/second
+if [ -z "$first" ]; then
+	echo "Usage: compare <branch name A> [<branch name B>]"
+	echo ""
+	echo "The second argument defaults to the current branch if not specified"
+	exit 1
+fi
 
 # Remember the branch we're on
 currentbranch=`git symbolic-ref --short HEAD`
 
+if [ -z "$second" ]; then
+	second=$currentbranch
+fi
+
+firstdir=comparison/first
+seconddir=comparison/second
+
 # Make sure the output directory exists
 mkdir -p comparison
 
@@ -19,8 +30,8 @@ rm -fr $seconddir
 export BREATHE_COMPARE=True
 
 # Checkout the first target
-echo git checkout $1
-git checkout $1
+echo git checkout $first
+git checkout $first
 # Run doxygen for this state
 (cd ../examples/specific; make)
 (cd ../examples/tinyxml; make)
@@ -36,8 +47,8 @@ git checkout Makefile
 
 
 # Checkout the second target and repeat
-echo git checkout $2
-git checkout $2
+echo git checkout $second
+git checkout $second
 (cd ../examples/specific; make)
 (cd ../examples/tinyxml; make)
 (cd ../examples/doxygen; make)