“No manual entry for help.”
A terminal is nothing more than a connection to a computer that allows you to type commands and have results displayed back to you. Terminals existed before the graphical user interface took hold. UNIX was originally a terminal-based operating system. DOS still is. Mac OS X offers the power of the terminal along with its elegant Aqua user interface allowing you to achieve greater control over your computer than you can with a graphical user interface alone.
Figure 13.1 shows the Terminal application packaged with Mac OS X. This application gives you all the options you would expect from a standard UNIX terminal. Using the terminal, you can perform file manipulation, process control, remote computer ...