1TTY(P) POSIX Programmer's Manual TTY(P)
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6 tty - return user's terminal name
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9 tty
10
12 The tty utility shall write to the standard output the name of the ter‐
13 minal that is open as standard input. The name that is used shall be
14 equivalent to the string that would be returned by the ttyname() func‐
15 tion defined in the System Interfaces volume of IEEE Std 1003.1-2001.
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18 The tty utility shall conform to the Base Definitions volume of
19 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
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22 None.
23
25 While no input is read from standard input, standard input shall be
26 examined to determine whether or not it is a terminal, and, if so, to
27 determine the name of the terminal.
28
30 None.
31
33 The following environment variables shall affect the execution of tty:
34 LANG Provide a default value for the internationalization variables
36 that are unset or null. (See the Base Definitions volume of
37 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
38 ables for the precedence of internationalization variables used
39 to determine the values of locale categories.)
40 LC_ALL If set to a non-empty string value, override the values of all
42 the other internationalization variables.
43 LC_CTYPE
45 Determine the locale for the interpretation of sequences of
46 bytes of text data as characters (for example, single-byte as
47 opposed to multi-byte characters in arguments).
48 LC_MESSAGES
50 Determine the locale that should be used to affect the format
51 and contents of diagnostic messages written to standard error
52 and informative messages written to standard output.
53 NLSPATH
55 Determine the location of message catalogs for the processing of
56 LC_MESSAGES .
57
60 Default.
61
63 If standard input is a terminal device, a pathname of the terminal as
64 specified by the ttyname() function defined in the System Interfaces
65 volume of IEEE Std 1003.1-2001 shall be written in the following for‐
66 mat:
67 "%s\n", <terminal name>
70 Otherwise, a message shall be written indicating that standard input is
72 not connected to a terminal. In the POSIX locale, the tty utility shall
73 use the format:
74 "not a tty\n"
77
79 The standard error shall be used only for diagnostic messages.
80
82 None.
83
85 None.
86
88 The following exit values shall be returned:
89 0 Standard input is a terminal.
91 1 Standard input is not a terminal.
93 >1 An error occurred.
95
98 Default.
99 The following sections are informative.
101
103 This utility checks the status of the file open as standard input
104 against that of an implementation-defined set of files. It is possible
105 that no match can be found, or that the match found need not be the
106 same file as that which was opened for standard input (although they
107 are the same device).
108
110 None.
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113 None.
114
116 None.
117
119 The System Interfaces volume of IEEE Std 1003.1-2001, isatty(), tty‐
120 name()
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123 Portions of this text are reprinted and reproduced in electronic form
124 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
125 -- Portable Operating System Interface (POSIX), The Open Group Base
126 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
127 Electrical and Electronics Engineers, Inc and The Open Group. In the
128 event of any discrepancy between this version and the original IEEE and
129 The Open Group Standard, the original IEEE and The Open Group Standard
130 is the referee document. The original Standard can be obtained online
131 at http://www.opengroup.org/unix/online.html .
132IEEE/The Open Group 2003 TTY(P)