contrib: Avoid redundant 'git diff' in prepare-commit-msg hook

contrib/ChangeLog:

	* prepare-commit-msg: Use 'tee' to save the diff to a file
	instead of running 'git diff' twice.

diff --git a/contrib/prepare-commit-msg b/contrib/prepare-commit-msg
index 24f0783aae24e59b7954dac3693ae598a3180db7..57bb91747f68f96d9dcc597ef7ec6c710c985ce4 100755 (executable)
--- a/contrib/prepare-commit-msg
+++ b/contrib/prepare-commit-msg
@@ -59,7 +59,9 @@ fi
 
 # Save diff to a file if requested.
 if ! [ -z "$GCC_GIT_DIFF_FILE" ]; then
-  git $cmd > "$GCC_GIT_DIFF_FILE";
+    tee="tee $GCC_GIT_DIFF_FILE"
+else
+    tee="cat"
 fi
 
-git $cmd | git gcc-mklog -c "$COMMIT_MSG_FILE"
+git $cmd | $tee | git gcc-mklog -c "$COMMIT_MSG_FILE"