The pwd utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported by the implementation:
If the PWD environment variable contains an absolute
pathname of the current directory that does not contain the filenames dot
or dot-dot, pwd shall write this pathname to standard output.
Otherwise, the -L option shall behave as the -P option.
The absolute pathname written shall not contain filenames
that, in the context of the pathname, refer to files of type symbolic
If both -L and -P are specified, the last one shall apply. If
neither -L nor -P is specified, the pwd utility shall
behave as if -L had been specified.
The following environment variables shall affect the execution of pwd:
Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization
Variables for the precedence of internationalization variables used to
determine the values of locale categories.)
If set to a non-empty string value, override the values of
all the other internationalization variables.
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to standard error.
Determine the location of message catalogs for the
processing of LC_MESSAGES.
If the -P option is in effect, this variable shall
be set to an absolute pathname of the current working directory that does
not contain any components that specify symbolic links, does not contain
any components that are dot, and does not contain any components that are
dot-dot. If an application sets or unsets the value of PWD , the
behavior of pwd is unspecified.
If an error is detected, output shall not be written to standard output, a
diagnostic message shall be written to standard error, and the exit status is
The following sections are informative.
Some implementations have historically provided pwd as a shell special
In most utilities, if an error occurs, partial output may be written to standard
output. This does not happen in historical implementations of pwd.
Because pwd is frequently used in historical shell scripts without
checking the exit status, it is important that the historical behavior is
required here; therefore, the CONSEQUENCES OF ERRORS section specifically
disallows any partial output being written to standard output.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html