basename(P)                                         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    volume    of
       IEEE Std 1003.1-2001,   Section   3.266,  Pathname.  The
       string string shall be converted to the filename  corre-
       sponding  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 equiv-
       alent to the following steps in order:

       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.

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

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

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

       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.

       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 suf-
       fix  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 out-
       put.

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 internationaliza-
              tion 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  cate-
              gories.)

       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 mes-
              sages 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 arbitrar-
       ily 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 path-
       name; 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 coordi-
       nated 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 implementa-
       tion-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 Operat-
       ing System Interface (POSIX), The Open Group Base Speci-
       fications Issue 6, Copyright (C) 2001-2003 by the Insti-
       tute 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 .



POSIX                         2003                  basename(P)
