Five useful Terminal commands for macOS

While everyone is preparing for Apple to release macOS 26 Tahoe and give their Mac a shiny new Liquid Glass look, there’s an under appreciated way to use your Mac. The Terminal is a powerful tool, that used correctly, can unlock hundreds of new ways to customise your Mac. 

Here are five of my favourite Terminal commands.

Before we start

As Uncle Ben said, “With great power comes great responsibility.” While the Terminal offers ways to customise your Mac it’s also possible to make a mess of your system if you don’t know what you’re doing. So, I advise that you make sure you have a reliable backup in place before you start playing around. 

I’m a big fan of the 3-2-1-0 backup method.  

How to start Terminal

The Terminal application is found in your Applications | Utilities folder.

Or you can launch it from Spotlight by simply searching for Terminal.

1 – Customise your calendar

Apple’s Calendar app has matured into a powerful tool. But there is one annoying feature that can be fixed through the Terminal. Apple has decided that the only views of your schedule you need are Day, Week, Month or Year. On today’s widescreens, you may find a 10-day of fortnightly view more useful for planning ahead.

Fortunately, you can use Terminal commands to customise the Week view to display however many days you want.

1. Launch Terminal
2. Type or copy/paste this command into Terminal

defaults write com.apple.iCal n\ days\ of\ week 14

3. When you go to Calendar, the Week view will now display 14 days. If you prefer 10 days, 2 days or some other number, simply change the 14 to the number of days you want. 
4. To revert back to the default seven days, simply reenter the command and change the last number to 7.

Note: If you’re using an older version of macOS or OS X, this command may not work. If that’s the case, this will work:

defaults write com.apple.iCal CalUIDebugDefaultDaysInWeekView XX

Just change the XX to the number of days you want to see.

2 – Screenshot formats

Apple’s inbuilt screenshot tools mean the need for third-party tools is almost zero. Command-Shift-4 lets you select an area to capture while Command-Shift-5 provides flexibility to choose where a screen capture is saved, whether to capture the whole screen a region or a specific window as well as the ability to set a delay. 

But, by default, screen captures are saved in PNG format.  But a simple command lets you choose the screen capture format.

1. Launch Terminal
2. Type or copy/paste this command into Terminal

defaults write com.apple.screencapture type jpg

This switches the default capture format to JPG. You can also choose from TIFF, GIF, PDF or RAW.

3 – Make your Mac talk to you

Apple’s text-to-speech and speech-to-text capabilities have been around for some time. But you can also make your Mac talk to you via Terminal by using the say command.

Try this.

1. Launch the Terminal
2. Type the following

say Hello. I’m your Mac

A couple of seconds later, your Mac will say those words.

You can choose from around 100 different voices. For example you can try 

say -v Zarvox Hello. I’m your Mac

Or

say -v Moira Hello. I’m your Mac

If you go to System Settings | Accessibility | Live Speech and click on the Voice dropdown you’ll see the list of available voices. If you click the ‘i” adjacent to the dropdown list you’ll see a list of all the voices you can download.

Just type the voice name after the ‘v’ in the command above and you’ll hear it.

4 – Caffeinate your Mac

Setting appropriate sleep time so your Mac uses less power after some inactivity is a good way to save some energy. But there may be times when you want your Mac to stay awake. 

Over the years, Apple has reduced the number of different power settings available through System Settings. But if you want to quickly stop your Mac from going to sleep you can type one simple word.

1. Launch the Terminal
2. Type the following

caffeinate

Your Mac will stay awake until either press Control-C or quit Terminal. 

If you want to set the time your Mac stays awake, you can use

caffeinate -u -t 3600

3600 is the number of seconds your Mac will stay awake. In this case, we’re telling the Mac to not go to sleep for an hour. 

5 – Check the weather

This is a pretty cool command. It uses the curl command which is used for transferring data from a server to your Mac using a variety of different protocols. For example, if you want to download a file from a website you could use 

curl -o [file_name] [URL]

But you can also check the local weather. 

1. Launch the Terminal
2. Type the following

curl https://wttr.in/      

Curl is a bit like the old Lynx web browser that predates graphical user interfaces to enable people to use the web via text-based systems.