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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  volume  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,    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.

       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  starting  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 original Standard can be  obtained  online
       at http://www.opengroup.org/unix/online.html .