diff --git a/misc/rb_optparse.zsh b/misc/rb_optparse.zsh
index 258d4f8..97fc19a 100644
--- a/misc/rb_optparse.zsh
+++ b/misc/rb_optparse.zsh
@@ -8,11 +8,11 @@
 #      cp rb_optparse.zsh ~/.zsh.d/rb_optparse.zsh
 #
 # (2) load the script, and add a directory to fpath before compinit.
-#      echo '. ~/.zsh.d/rb_optparse.zsh' >> "${ZDOTDIR:-~}/.zshrc"
-#      echo 'fpath=(~/.zsh.d/Completion $fpath)' >> "${ZDOTDIR:-~}/.zshrc"
-#      echo 'autoload -U compinit; compinit' >> "${ZDOTDIR:-~}/.zshrc"
+#      echo '. ~/.zsh.d/rb_optparse.zsh' >> "${ZDOTDIR:-$HOME}/.zshrc"
+#      echo 'fpath=(~/.zsh.d/Completion $fpath)' >> "${ZDOTDIR:-$HOME}/.zshrc"
+#      echo 'autoload -U compinit; compinit' >> "${ZDOTDIR:-$HOME}/.zshrc"
 #
-# (3) restart zsh.
+# (3) restart zsh. (eg `exec zsh -il`)
 #
 # (4) generate completion files once.
 #      generate-complete-function/ruby/optparse COMMAND1