export GIT_AUTHOR_EMAIL="$_author"
        "$@"
-        export GIT_AUTHOR_EMAIL="$_save"
+       if test -z "$_save"
+       then
+               unset GIT_AUTHOR_EMAIL
+       else
+               export GIT_AUTHOR_EMAIL="$_save"
+       fi
 }
 
 commit_date()
 {
     _date=$1
     shift 1
-    GIT_COMMITTER_DATE=$_date "$@"
+    export GIT_COMMITTER_DATE="$_date"
+    "$@"
+    unset GIT_COMMITTER_DATE
 }
 
 # Execute a command and suppress any error output.