The Typographical Correction
macOS includes a built-in text substitution engine designed to make your writing look more professional. One of its default behaviours is converting standard straight quotation marks (the kind typically generated by your keyboard) into “smart quotes” (curly quotation marks that slope towards the enclosed text). While this is excellent for writing essays or emails, it is highly disruptive if you are writing code snippets, shell scripts, or specific markup languages where straight quotes are syntactically required. This automatic conversion can break scripts and cause frustrating syntax errors.
Disabling Smart Quotes
You can turn off this typographical substitution globally across the entire operating system, meaning macOS will respect exactly what you type without attempting to style the punctuation. Open the System Settings application from your Dock or the Apple Menu.
In the left-hand sidebar, navigate to Keyboard. Scroll down the main pane until you find the “Text Input” section, and click the Edit… button next to your primary input source (usually your language keyboard). A new dialogue box will appear containing various spelling and grammar options. Locate the toggle switch labelled Use smart quotes and dashes and turn it completely off. Click Done to save your changes. From this point forward, macOS will strictly output straight quotes when you press the quotation mark key on your keyboard.