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Much like Windows, Linux has support for four-digit codes that call special symbols. To access the code input, place your cursor where you want the dash and press Ctrl+⇧ Shift+U. You will see an underlined “u” appear. Enter the code you need and the symbol will appear.  To create an en dash, press 2013 and then press ↵ Enter. To create an em dash, press 2014 and then press ↵ Enter. If your keyboard doesn't have a dedicated Compose key, you can assign a key on your keyboard to become the ⎄ Compose key, which will allow you to quickly create symbols. You should pick a key that you don’t typically use.  To map the ⎄ Compose key, open your Settings in Linux, and then select Keyboard Layout. Click Options and then assign a key on your keyboard to be the ⎄ Compose key. To create an en dash, press ⎄ Compose and then --. To create an em dash, press ⎄ Compose and then ---
Use codes to create dashes. Use the Compose key.