Specifications

Logging In from Terminal
To open Terminal, click the Terminal icon in the dock or double-click the application
icon in the Finder (in /Applications/Utilities/). Each window in Terminal represents
another instance of a shell process.
Terminal presents a prompt when it’s ready to accept a command. The prompt you
see depends on your Terminal and shell preferences, but it often includes the name
of the host you’re logged in to, your current working folder, your user name, and
a prompt symbol.
For example, if you’re using the default bash shell, the prompt appears as:
server1:~ mariah$
This indicates that you’re logged in to a computer named server1 as the user named
mariah, and your current folder is Mariah’s home folder (~).
Logging In from the Console
You can log in to a command-line version of Mac OS X without running the window
manager. This mode is more advanced than single-user mode because the entire
system is running.
To log in without the window manager:
1 In the Accounts pane of System Preferences, select Login Options.
2 Make sure the settings for “Display login window as:” is set to “Name and password.”
3 Log out any logged in users.
4 In the login window, type “>console” and press Return. Don’t enter a password.
You’ll be prompted to log in with the user name and password of a user on
the system.
Logging in to the console at this level can help you troubleshoot issues that
are graphics-related or that are triggered by users logging in to the system
through the GUI.
Single-User Mode
To debug a computer problem, you can restart the computer and hold down
Command-S as the computer boots. The computer boots up verbosely from
the command line to a certain point, and won’t continue booting without your
intervention. The window server won’t be running, and many services won’t be started.
Onscreen instructions guide you through mounting and verifying the attached
volumes. This is a useful way to boot if you want to troubleshoot hardware-related
issues or determine what’s happening in software before higher-level processes and
applications are running. At this point, very few processes are running.
12 Chapter 1 Introduction to the Command-Line Environment