Add get_blob and get_commit_for_blob

git_helpers

@@ -224,4 +224,20 @@ changed_file_names () {
             "while in $PWD"
     fi
 }
-# fi
+
+get_blob () {   # get the blob of the file(name) passed as $1
+                # note: this can be used for any file in the filesystem
+    echo $(git hash-object $1)
+}
+
+get_commit_for_blob () {
+    blob=$(get_blob $1)
+    if [ ! -z $blob ]; then
+        # search for the blob in all commits for the file(name) $1
+        echo $(echo $(git log --all --pretty=format:%H -- $1) |
+               xargs -I{} sh -c "git ls-tree {} -- $1         |
+               grep -q $blob && echo {}")
+    fi
+}
+
+