A key tool to the System Administrator or the more advanced user of any Unix/Linux/OS X system is the Command Line Interface (CLI) and that is accessed on OS X systems through the Terminal App. Apple includes the Terminal App with the Utilities. To open the Terminal App got to Finder >> Go >> Utilities >> Terminal.
When the Terminal opens by default it will be at the Home directory for the user. Now the user can enter any commands into the terminal for execution.
If you want to adjust the font size used, you can do so by using the Command+Plus (+) key combination to increase the font size, or Command+Minus (-) to decrease the font size. Using Command-Zero (0) will return the font size to the default.
Through the Terminal Preferences you can also adjust the colors being used to find a background/foreground color combination to your liking. The example above is with the ‘Basic’ profile while the one below is using the ‘Homebrew’ profile.
I find that the ‘Homebrew’ profile provied more contrast and makes the Terminal content easier to read.
A simple ‘Terminal Cheatsheet for Mac‘ gives an over view of keyboard shortcuts for the Terminal App., as well as the most common CLI commands you might use.
See my other SysAdmin articles