BASENAME(1)                POSIX Programmer's Manual               BASENAME(1)



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NNAAMMEE
       basename -- return non-directory portion of a pathname

SSYYNNOOPPSSIISS
       basename _s_t_r_i_n_g [[_s_u_f_f_i_x]]

DDEESSCCRRIIPPTTIIOONN
       The _s_t_r_i_n_g operand shall be treated as a pathname, as defined in the
       Base Definitions volume of POSIX.1-2017, _S_e_c_t_i_o_n _3_._2_7_1, _P_a_t_h_n_a_m_e.  The
       string _s_t_r_i_n_g shall be converted to the filename corresponding to the
       last pathname component in _s_t_r_i_n_g and then the suffix string _s_u_f_f_i_x, if
       present, shall be removed. This shall be done by performing actions
       equivalent to the following steps in order:

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

        3. If _s_t_r_i_n_g consists entirely of <slash> characters, _s_t_r_i_n_g 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 _s_t_r_i_n_g, they shall
           be removed.

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

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

       The resulting string shall be written to standard output.

OOPPTTIIOONNSS
       None.

OOPPEERRAANNDDSS
       The following operands shall be supported:

       _s_t_r_i_n_g    A string.

       _s_u_f_f_i_x    A string.

SSTTDDIINN
       Not used.

IINNPPUUTT FFIILLEESS
       None.

EENNVVIIRROONNMMEENNTT VVAARRIIAABBLLEESS
       The following environment variables shall affect the execution of
       _b_a_s_e_n_a_m_e:

       _L_A_N_G      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base Definitions
                 volume of POSIX.1-2017, _S_e_c_t_i_o_n _8_._2, _I_n_t_e_r_n_a_t_i_o_n_a_l_i_z_a_t_i_o_n
                 _V_a_r_i_a_b_l_e_s for the precedence of internationalization
                 variables used to determine the values of locale categories.)

       _L_C___A_L_L    If set to a non-empty string value, override the values of
                 all the other internationalization variables.

       _L_C___C_T_Y_P_E  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).

       _L_C___M_E_S_S_A_G_E_S
                 Determine the locale that should be used to affect the format
                 and contents of diagnostic messages written to standard
                 error.

       _N_L_S_P_A_T_H   Determine the location of message catalogs for the processing
                 of _L_C___M_E_S_S_A_G_E_S.

AASSYYNNCCHHRROONNOOUUSS EEVVEENNTTSS
       Default.

SSTTDDOOUUTT
       The _b_a_s_e_n_a_m_e utility shall write a line to the standard output in the
       following format:


           "%s\n", <_r_e_s_u_l_t_i_n_g _s_t_r_i_n_g>

SSTTDDEERRRR
       The standard error shall be used only for diagnostic messages.

OOUUTTPPUUTT FFIILLEESS
       None.

EEXXTTEENNDDEEDD DDEESSCCRRIIPPTTIIOONN
       None.

EEXXIITT SSTTAATTUUSS
       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CCOONNSSEEQQUUEENNCCEESS OOFF EERRRROORRSS
       Default.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       The definition of _p_a_t_h_n_a_m_e specifies implementation-defined behavior
       for pathnames starting with two <slash> characters. Therefore,
       applications shall not arbitrarily add <slash> characters 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.

EEXXAAMMPPLLEESS
       If the string _s_t_r_i_n_g is a valid pathname:


           $(basename -- "_s_t_r_i_n_g")

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


           $(dirname -- "_s_t_r_i_n_g")

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

       The following shell script compiles //uussrr//ssrrcc//ccmmdd//ccaatt..cc and moves the
       output to a file named ccaatt in the current directory when invoked with
       the argument //uussrr//ssrrcc//ccmmdd//ccaatt or with the argument //uussrr//ssrrcc//ccmmdd//ccaatt..cc:


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

       The EXAMPLES section of the _b_a_s_e_n_a_m_e() function (see the System
       Interfaces volume of POSIX.1-2017, _b_a_s_e_n_a_m_e()) includes a table showing
       examples of the results of processing several sample pathnames by the
       _b_a_s_e_n_a_m_e() and _d_i_r_n_a_m_e() functions and by the _b_a_s_e_n_a_m_e and _d_i_r_n_a_m_e
       utilities.

RRAATTIIOONNAALLEE
       The behaviors of _b_a_s_e_n_a_m_e and _d_i_r_n_a_m_e have been coordinated so that
       when _s_t_r_i_n_g is a valid pathname:


           $(basename -- "_s_t_r_i_n_g")

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


           $(dirname -- "_s_t_r_i_n_g")

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

       Since the definition of _p_a_t_h_n_a_m_e specifies implementation-defined
       behavior for pathnames starting with two <slash> characters, this
       volume of POSIX.1-2017 specifies similar implementation-defined
       behavior for the _b_a_s_e_n_a_m_e and _d_i_r_n_a_m_e utilities.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _S_e_c_t_i_o_n _2_._5, _P_a_r_a_m_e_t_e_r_s _a_n_d _V_a_r_i_a_b_l_e_s, _d_i_r_n_a_m_e

       The Base Definitions volume of POSIX.1-2017, _S_e_c_t_i_o_n _3_._2_7_1, _P_a_t_h_n_a_m_e,
       _C_h_a_p_t_e_r _8, _E_n_v_i_r_o_n_m_e_n_t _V_a_r_i_a_b_l_e_s

       The System Interfaces volume of POSIX.1-2017, _b_a_s_e_n_a_m_e(), _d_i_r_n_a_m_e()

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                          BASENAME(1)
