This is documentation for Mathematica 6, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.1)

Text-Based Interfaces

maththe operating system command to start Mathematica
text ending with Enterinput for Mathematica
Ctrl+D or Quit[]exiting Mathematica

Running Mathematica with a text-based interface.

With a text-based interface, you interact with your computer primarily by typing text on the keyboard.
To start Mathematica with a text-based interface, you typically type the command math at an operating system prompt. On some systems, you may also be able to start Mathematica with a text-based interface by double-clicking a Mathematica kernel icon.
When Mathematica has started, it will print the prompt In[1]:=, signifying that it is ready for your input. You can then type your input, ending with Enter or Return.
Mathematica will then process the input, and generate a result. If it prints the result out, it will label it with Out[1]=.
In Mathematica reference documents, dialogs with Mathematica are shown in the following way:
The computer prints In[1]:=. You just type in 2+2. The line that starts with Out[1]= is the result from Mathematica.
Click for copyable input
Note that you do not explicitly type the In[n]:= prompt; only type the text that follows this prompt.
Note also that most of the actual dialogs given in the Mathematica tutorials show output in the form you get with a notebook interface to Mathematica; output with a text-based interface looks similar, but lacks such features as special characters and font size changes.
"Using the Mathematica System" gives more details on running Mathematica with a text-based interface. To exit Mathematica, either type Ctrl+D, Ctrl+Z or Quit[] at an input prompt.