NAME
pwd — return
working directory name
SYNOPSIS
pwd |
[-L | -P] |
DESCRIPTION
The pwd utility shall write to standard
output an absolute pathname of the current working directory, which does not
contain the filenames dot or dot-dot.
OPTIONS
The pwd utility shall conform to XBD
V1_chap12(7).
The following options shall be supported by the implementation:
-L- If the PWD environment variable contains an absolute pathname of the
current directory and the pathname does not contain any components that
are dot or dot-dot,
pwdshall write this pathname to standard output, except that if the PWD environment variable is longer than {PATH_MAX} bytes including the terminating null, it is unspecified whetherpwdwrites this pathname to standard output or behaves as if the-Poption had been specified. Otherwise, the-Loption shall behave as the-Poption. -P- The pathname written to standard output shall not contain any components
that refer to files of type symbolic link. If there are multiple pathnames
that the
pwdutility could write to standard output, one beginning with a single <slash> character and one or more beginning with two <slash> characters, then it shall write the pathname beginning with a single <slash> character. The pathname shall not contain any unnecessary <slash> characters after the leading one or two <slash> characters.
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.
OPERANDS
None.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of
pwd:
LANG- Provide a default value for the internationalization variables that are unset or null. (See XBD 8.2 Internationalization Variables 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_MESSAGES-
Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error. NLSPATH- [
XSI] Determine the location of messages objects and message catalogs. PWD- An absolute pathname of the current working directory. If an application
sets or unsets the value of PWD , the behavior of
pwdis unspecified.
ASYNCHRONOUS EVENTS
Default.
STDOUT
The pwd utility output is an absolute
pathname of the current working directory:
"%s\n", <directory pathname>
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:
CONSEQUENCES OF ERRORS
If an error is detected other than a write error when writing to standard output, no output shall be written to standard output, a diagnostic message shall be written to standard error, and the exit status shall be non-zero.
APPLICATION USAGE
If the pathname obtained from pwd is
longer than {PATH_MAX} bytes, it could produce an error if passed to
cd(1). Therefore, in order to return to that directory it
may be necessary to break the pathname into sections shorter than {PATH_MAX}
and call cd(1) on each section in turn (the first section
being an absolute pathname and subsequent sections being relative
pathnames).
EXAMPLES
None.
RATIONALE
Some implementations have historically provided
pwd as a shell special built-in command.
In most utilities, if an error occurs, partial output may be
written to standard output. This does not happen in historical
implementations of pwd (unless an error condition
causes a partial write). 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, except when a write error occurs when
writing to standard output.
An earlier version of this standard stated that the
PWD environment variable was affected when the
-P option was in effect. This was incorrect;
conforming implementations do not do this.
FUTURE DIRECTIONS
If this utility is directed to display a pathname that contains any bytes that have the encoded value of a <newline> character when <newline> is a terminator or separator in the output format being used, implementations are encouraged to treat this as an error. A future version of this standard may require implementations to treat this as an error.
SEE ALSO
XBD V1_chap08(7), V1_chap12(7)
XSH getcwd(3)
CHANGE HISTORY
First released in Issue 2.
Issue 6
The -P and -L
options are added to describe actions relating to symbolic links as
specified in the IEEE P1003.2b draft standard.
Issue 7
Austin Group Interpretation 1003.1-2001 #097 is applied.
SD5-XCU-ERN-97 is applied, updating the SYNOPSIS.
Changes to the pwd utility and
PWD environment variable have been made to match the
changes to the getcwd(3) function made for Austin Group
Interpretation 1003.1-2001 #140.
POSIX.1-2008, Technical Corrigendum 2, XCU/TC2-2008/0161 [471] is applied.
Issue 8
Austin Group Defect 251 is applied, encouraging implementations to report an error if a utility is directed to display a pathname that contains any bytes that have the encoded value of a <newline> character when <newline> is a terminator or separator in the output format being used.
Austin Group Defect 1122 is applied, changing the description of NLSPATH .
Austin Group Defect 1488 is applied, clarifying the behavior when a write error occurs when writing to standard output.