ttyposix - Online in the Cloud

This is the command ttyposix that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

PROGRAM:

NAME


tty — return user's terminal name

SYNOPSIS


tty

DESCRIPTION


The tty utility shall write to the standard output the name of the terminal that is open
as standard input. The name that is used shall be equivalent to the string that would be
returned by the ttyname() function defined in the System Interfaces volume of
POSIX.1‐2008.

OPTIONS


The tty utility shall conform to the Base Definitions volume of POSIX.1‐2008, Section
12.2, Utility Syntax Guidelines.

OPERANDS


None.

STDIN


While no input is read from standard input, standard input shall be examined to determine
whether or not it is a terminal, and, if so, to determine the name of the terminal.

INPUT FILES


None.

ENVIRONMENT VARIABLES


The following environment variables shall affect the execution of tty:

LANG Provide a default value for the internationalization variables that are unset or
null. (See the Base Definitions volume of POSIX.1‐2008, Section 8.2,
Internationalization Variables for the precedence of internationalization
variables used to determine the values of locale categories.)

LC_ALL If set to a non-empty string value, override the values of all the other
internationalization variables.

LC_CTYPE Determine the locale for the interpretation of sequences of bytes of text data
as characters (for example, single-byte as opposed to multi-byte characters in
arguments).

LC_MESSAGES
Determine the locale that should be used to affect the format and contents of
diagnostic messages written to standard error and informative messages written
to standard output.

NLSPATH Determine the location of message catalogs for the processing of LC_MESSAGES.

ASYNCHRONOUS EVENTS


Default.

STDOUT


If standard input is a terminal device, a pathname of the terminal as specified by the
ttyname() function defined in the System Interfaces volume of POSIX.1‐2008 shall be
written in the following format:

"%s\n", <terminal name>

Otherwise, a message shall be written indicating that standard input is not connected to a
terminal. In the POSIX locale, the tty utility shall use the format:

"not a tty\n"

STDERR


The standard error shall be used only for diagnostic messages.

OUTPUT FILES


None.

EXTENDED DESCRIPTION


None.

EXIT STATUS


The following exit values shall be returned:

0 Standard input is a terminal.

1 Standard input is not a terminal.

>1 An error occurred.

CONSEQUENCES OF ERRORS


Default.

The following sections are informative.

APPLICATION USAGE


This utility checks the status of the file open as standard input against that of an
implementation-defined set of files. It is possible that no match can be found, or that
the match found need not be the same file as that which was opened for standard input
(although they are the same device).

EXAMPLES


None.

RATIONALE


None.

FUTURE DIRECTIONS


None.

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