docs: update

README.md

@@ -80,6 +80,9 @@ See something incorrectly described, buggy or outright wrong? Open an issue or s
     * [Get the current working directory](#get-the-current-working-directory)
     * [Get the PID of the current shell](#get-the-pid-of-the-current-shell)
     * [Get the current shell options](#get-the-current-shell-options)
+* [SHELL QUIRKS](#shell-quirks)
+    * [`shift` with no function arguments crashes `dash`.](#shift-with-no-function-arguments-crashes-dash)
+    * [`read` with no given variable crashes `dash`.](#read-with-no-given-variable-crashes-dash)
 * [AFTERWORD](#afterword)
 
 <!-- vim-markdown-toc -->
@@ -858,6 +861,31 @@ This is an alternative to the `pwd` built-in.
 "$-"
 ```
 
+# SHELL QUIRKS
+
+## `shift` with no function arguments crashes `dash`.
+
+```shell
+# This will crash `dash` if there are no arguments.
+shift
+
+# Solution (shift on its own is really 'shift 1').
+# This uses 'shift 0' if there are no arguments and
+# 'shift 1' if there are.
+shift "$(($# > 0 ? 1 : 0))"
+```
+
+## `read` with no given variable crashes `dash`.
+
+```shell
+# This will crash `dash`.
+read -r
+
+# Solution.
+# Use a dummy variable.
+read -r _
+```
+
 # AFTERWORD
 
 Thanks for reading! If this bible helped you in any way and you'd like to give back, consider donating. Donations give me the time to make this the best resource possible. Can't donate? That's OK, star the repo and share it with your friends!