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BASENAME(P)			    POSIX Programmer's Manual			      BASENAME(P)

NAME
       basename - return non-directory portion of a pathname

SYNOPSIS
       basename string [suffix]

DESCRIPTION
       The string operand shall be treated as a pathname, as defined in the Base Definitions vol-
       ume of IEEE Std 1003.1-2001, Section 3.266, Pathname. The string string shall be converted
       to the filename corresponding to the last pathname component in string and then the suffix
       string suffix, if present, shall be removed. This shall	be  done  by  performing  actions
       equivalent to the following steps in order:

	1. If string is a null string, it is unspecified whether the resulting string is '.' or a
	   null string. In either case, skip steps 2 through 6.

	2. If string is "//" , it is implementation-defined whether steps 3 to 6 are  skipped  or
	   processed.

	3. If string consists entirely of slash characters, string shall be set to a single slash
	   character. In this case, skip steps 4 to 6.

	4. If there are any trailing slash characters in string, they shall be removed.

	5. If there are any slash characters remaining in string, the prefix of string up to  and
	   including the last slash character in string shall be removed.

	6. If  the  suffix  operand  is  present, is not identical to the characters remaining in
	   string, and is identical to a suffix of the characters remaining in string, the suffix
	   suffix  shall  be removed from string. Otherwise, string is not modified by this step.
	   It shall not be considered an error if suffix is not found in string.

       The resulting string shall be written to standard output.

OPTIONS
       None.

OPERANDS
       The following operands shall be supported:

       string A string.

       suffix A string.

STDIN
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of basename:

       LANG   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, Inter-
	      nationalization 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 interna-
	      tionalization 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 argu-
	      ments).

       LC_MESSAGES
	      Determine the locale that should be used to affect the format and contents of diag-
	      nostic messages written to standard error.

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

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       The basename utility shall write a line to the standard output in the following format:

	      "%s\n", <resulting string>

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     Successful completion.

       >0     An error occurred.

CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       The  definition of pathname specifies implementation-defined behavior for pathnames start-
       ing with two slash characters.  Therefore, applications shall not arbitrarily add  slashes
       to the beginning of a pathname unless they can ensure that there are more or less than two
       or are prepared to deal with the implementation-defined consequences.

EXAMPLES
       If the string string is a valid pathname:

	      $(basename "string")

       produces a filename that could be used to open the file named by string in  the	directory
       returned by:

	      $(dirname "string")

       If  the	string string is not a valid pathname, the same algorithm is used, but the result
       need not be a valid filename.  The basename utility is not expected to make any judgements
       about  the  validity  of  string as a pathname; it just follows the specified algorithm to
       produce a result string.

       The following shell script compiles /usr/src/cmd/cat.c and moves  the  output  to  a  file
       named cat in the current directory when invoked with the argument /usr/src/cmd/cat or with
       the argument /usr/src/cmd/cat.c:

	      c99 $(dirname "$1")/$(basename "$1" .c).c
	      mv a.out $(basename "$1" .c)

RATIONALE
       The behaviors of basename and dirname have been coordinated so that when string is a valid
       pathname:

	      $(basename "string")

       would be a valid filename for the file in the directory:

	      $(dirname "string")

       This  would  not work for the early proposal versions of these utilities due to the way it
       specified handling of trailing slashes.

       Since the definition of pathname specifies implementation-defined behavior  for	pathnames
       starting  with two slash characters, this volume of IEEE Std 1003.1-2001 specifies similar
       implementation-defined behavior for the basename and dirname utilities.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Parameters and Variables , dirname()

COPYRIGHT
       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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003				      BASENAME(P)
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