introduction.9 (2010 09)

introduction(9) introduction(9)
uppercase input as lowercase.
When you log in successfully, the system starts your login shell. The default is the POSIX shell,
/usr/bin/sh. The POSIX shell (and its predecessors, the Korn and Bourne shells) use
$ as the default
prompt for users. The C shell uses
%
. All the shells use # as the default superuser prompt.
See login (1) for more on login, passwd (1) to change your password, chsh(1) to change your login shell.
Logging Out
You can log out of the shells by typing an
exit command or the eof (end-of-file) character (see the Spe-
cial Interactive Characters subsection below). The shell terminates and the
login: prompt appears
again. (If you are using the C, Korn, or POSIX shells, respectively, see csh(1), ksh (1), or sh-posix (1) for
information about the
ignoreeof special command.)
How to Communicate Through Your Terminal
HP-UX gathers keyboard input characters and saves them in a buffer. The accumulated characters are
not passed to the shell or other program until you type Enter.
HP-UX terminal input/output is full-duplex. It has full read-ahead, which means that you can type at
any time, even while a program is printing on your display or terminal. Of course, if you type during out-
put, the output display will have the input characters interspersed in it. However, whatever you type will
be saved and interpreted in the correct sequence. There is a limit to the amount of read-ahead, but it is
generous and not likely to be exceeded unless the system is severely overloaded or operating abnormally.
When the read-ahead limit is exceeded, the system throws away all the saved characters.
The stty (1) manpage tells you how to describe the characteristics of your terminal to the system. The
profile(4) manpage explains how to accomplish this task automatically every time you log in.
Special Interactive Characters
A number of special characters are used to control the input and output of your terminal. These charac-
ters have defaults and can be redefined with the
stty command (see stty (1)). Definitions of the
stty
names are in termio (7) and termiox (7).
Note : The system administrator can modify the system login defaults by changing the characteristics of
the
/dev/ttyconf device file with the stty command.
stty System Default At Login Common User
Name Character (ASCII Name; Key Names) Redefinition
eof ^D (EOT)
erase # ^H (BS; Backspace)
kill @ ^U (NAK), ˆX (CAN)
intr ^? (DEL; Delete, Rub, Rubout) ^C (ETX)
quit ^\ (FS)
start ˆQ (DC1; X-ON)
stop ^S (DC3; X-OFF)
The eof character terminates "file" input from the terminal, as read by programs and scripts. By exten-
sion, eof can also terminate the shell (see the Logging Out subsection above).
The
erase character erases the last character typed. Successive uses of erase will erase characters
back to, but not beyond, the beginning of the input line.
The
kill character deletes all characters typed before it on a terminal input line.
The
intr character generates an interrupt signal that bypasses the input buffer. This signal generally
causes whatever program you are running to terminate. It can be used to stop a long printout that you
don’t want. However, programs can arrange either to ignore this signal altogether, or to be notified when
it happens (instead of being terminated). For example, the vi editor catches interrupts and stops what it
is doing, instead of terminating, so that an interrupt can be used to halt an editing operation without los-
ing the file being edited.
The
quit character generates a quit signal that bypasses the input buffer and most program traps and
causes a running program to terminate. It can cause a core dump in the current directory.
The
stop character can be used to pause output to the terminal. It is commonly used on video terminals
to suspend output to the display while you read what is already being displayed. You can then resume
output by typing the start character. When stop and start are used to suspend or resume output,
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