DIRNAME(1)                 POSIX Programmer's Manual                DIRNAME(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
       dirname -- return the directory portion of a pathname

SSYYNNOOPPSSIISS
       dirname _s_t_r_i_n_g

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 name of the directory
       containing the filename corresponding to the last pathname component in
       _s_t_r_i_n_g, performing actions equivalent to the following steps in order:

        1. If _s_t_r_i_n_g is ////, skip steps 2 to 5.

        2. 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 3 to 8.

        3. If there are any trailing <slash> characters in _s_t_r_i_n_g, they shall
           be removed.

        4. If there are no <slash> characters remaining in _s_t_r_i_n_g, _s_t_r_i_n_g
           shall be set to a single <period> character. In this case, skip
           steps 5 to 8.

        5. If there are any trailing non-<slash> characters in _s_t_r_i_n_g, they
           shall be removed.

        6. If the remaining _s_t_r_i_n_g is ////, it is implementation-defined whether
           steps 7 and 8 are skipped or processed.

        7. If there are any trailing <slash> characters in _s_t_r_i_n_g, they shall
           be removed.

        8. If the remaining _s_t_r_i_n_g is empty, _s_t_r_i_n_g shall be set to a single
           <slash> character.

       The resulting string shall be written to standard output.

OOPPTTIIOONNSS
       None.

OOPPEERRAANNDDSS
       The following operand shall be supported:

       _s_t_r_i_n_g    A string.

SSTTDDIINN
       Not used.

IINNPPUUTT FFIILLEESS
       None.

EENNVVIIRROONNMMEENNTT VVAARRIIAABBLLEESS
       The following environment variables shall affect the execution of
       _d_i_r_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 _d_i_r_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
       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.

       See also the examples for the _b_a_s_e_n_a_m_e utility.

RRAATTIIOONNAALLEE
       The behaviors of _b_a_s_e_n_a_m_e and _d_i_r_n_a_m_e in this volume of POSIX.1-2017
       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 versions of these utilities in early
       proposals due to the way processing of trailing <slash> characters was
       specified. Consideration was given to leaving processing unspecified if
       there were trailing <slash> characters, but this cannot be done; 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 allows
       trailing <slash> characters. The _b_a_s_e_n_a_m_e and _d_i_r_n_a_m_e utilities have to
       specify consistent handling for all valid pathnames.

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, _b_a_s_e_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                           DIRNAME(1)
