am: fix signoff when other trailers are present

diff --git a/shell.c b/shell.c
index 464ee1a201ff014c390ddfd653088f7dffd13a84..fe2d314593ba5ee3b985b778c2e7ebfdcd9da44c 100644 (file)
--- a/shell.c
+++ b/shell.c
@@ -13,7 +13,7 @@ static int do_generic_cmd(const char *me, char *arg)
        const char *my_argv[4];
 
        setup_path();
-       if (!arg || !(arg = sq_dequote(arg)))
+       if (!arg || !(arg = sq_dequote(arg)) || *arg == '-')
                die("bad argument");
        if (!starts_with(me, "git-"))
                die("bad command");