Add script to perform signoff check between commits (#152)

* Add script to perform signoff check between commits

Signed-off-by: Peter Nied <petern@amazon.com>

dev-tools/signoff-check.sh

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+### Script to check for signoff presents on commits
+
+# Validate input parameters
+if [ -z $1 ] || [ -z $2 ]
+then
+   echo usage: ./signoff-check.sh commit1 commit2
+   echo
+   echo Checks all of the commits between commit1 \(exclusive\) and commit2 \(inclusive\)
+   echo were made with the --signoff flag enabled
+   exit 1
+fi
+
+# Get the list of commit ids to check from git
+commits=$(git rev-list $1..$2)
+
+# Scan each commit for the sign off message
+missingSignoff=0
+for commitId in $commits; do
+    commitMessage=$(git rev-list --format=%B --max-count=1 $commitId)
+    signoffStringCount=$(echo $commitMessage | grep -c Signed-off-by)
+    if [ $signoffStringCount -eq 0 ]; then
+      echo !!! Commit "$commitId" is missing signoff, amend this commit with the --signoff flag
+      let "missingSignoff++"
+    fi
+done
+
+# Return non-zero error code if any commits were missing signoff
+exit $missingSignoff
+