diff --git a/home/bashrc b/home/bashrc
index 5d98e70..76fb362 100644
--- a/home/bashrc
+++ b/home/bashrc
@@ -38,7 +38,7 @@ ADDPATH "$HOME/sh"
     # unlike zsh, we do not check the sha1sum of the output.
     cd ~/sh \
      && printf "%s\n" '#!/usr/bin/env false' '[ -n "$preload" ] || exit 1' '' \
-      | cat - $(grep -lF 'YES_BASH' $(find ~/sh -maxdepth 1 -type f)) \
+      | cat - $(grep -lF YES_BASH -- $(find ~/sh -maxdepth 1 -type f)) \
       > ~/.sh-bash
 )
 
diff --git a/home/zshrc b/home/zshrc
index 01813aa..902455b 100644
--- a/home/zshrc
+++ b/home/zshrc
@@ -57,7 +57,7 @@ function {
     [ -s ~/.sh.sha1 ] && read -r b _ < ~/.sh.sha1
     ( cd ~/sh \
       && print -l '#!/usr/bin/env false' '[ -n "$preload" ] || exit 1' '' \
-      | cat - $(grep -lF 'YES_ZSH' *~*.bak(.)) \
+      | cat - $(grep -lF YES_ZSH -- *~*.bak(.)) \
       | tee ~/.sh \
     ) | sha1sum - \
       | tee ~/.sh.sha1 \