DF(1)                      POSIX Programmer's Manual                     DF(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
       df -- report free disk space

SSYYNNOOPPSSIISS
       df [[-k]] [[-P|-t]] [[_f_i_l_e...]]

DDEESSCCRRIIPPTTIIOONN
       The _d_f utility shall write the amount of available space and file slots
       for file systems on which the invoking user has appropriate read
       access. File systems shall be specified by the _f_i_l_e operands; when none
       are specified, information shall be written for all file systems. The
       format of the default output from _d_f is unspecified, but all space
       figures are reported in 512-byte units, unless the --kk option is
       specified. This output shall contain at least the file system names,
       amount of available space on each of these file systems, and, if no
       options other than --tt are specified, the number of free file slots, or
       _i_n_o_d_es, available; when --tt is specified, the output shall contain the
       total allocated space as well.

OOPPTTIIOONNSS
       The _d_f utility shall conform to the Base Definitions volume of
       POSIX.1-2017, _S_e_c_t_i_o_n _1_2_._2, _U_t_i_l_i_t_y _S_y_n_t_a_x _G_u_i_d_e_l_i_n_e_s.

       The following options shall be supported:

       --kk        Use 1024-byte units, instead of the default 512-byte units,
                 when writing space figures.

       --PP        Produce output in the format described in the STDOUT section.

       --tt        Include total allocated-space figures in the output.

OOPPEERRAANNDDSS
       The following operand shall be supported:

       _f_i_l_e      A pathname of a file within the hierarchy of the desired file
                 system.  If a file other than a FIFO, a regular file, a
                 directory, or a special file representing the device
                 containing the file system (for example, //ddeevv//ddsskk//00ss11) is
                 specified, the results are unspecified. If the _f_i_l_e operand
                 names a file other than a special file containing a file
                 system, _d_f shall write the amount of free space in the file
                 system containing the specified _f_i_l_e operand.  Otherwise, _d_f
                 shall write the amount of free space in that file system.

SSTTDDIINN
       Not used.

IINNPPUUTT FFIILLEESS
       None.

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

       _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
                 and informative messages written to standard output.

       _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
       When both the --kk and --PP options are specified, the following header
       line shall be written (in the POSIX locale):


           "Filesystem 1024-blocks Used Available Capacity Mounted on\n"

       When the --PP option is specified without the --kk option, the following
       header line shall be written (in the POSIX locale):


           "Filesystem 512-blocks Used Available Capacity Mounted on\n"

       The implementation may adjust the spacing of the header line and the
       individual data lines so that the information is presented in orderly
       columns.

       The remaining output with --PP shall consist of one line of information
       for each specified file system. These lines shall be formatted as
       follows:


           "%s %d %d %d %d%% %s\n", <_f_i_l_e _s_y_s_t_e_m _n_a_m_e>, <_t_o_t_a_l _s_p_a_c_e>,
               <_s_p_a_c_e _u_s_e_d>, <_s_p_a_c_e _f_r_e_e>, <_p_e_r_c_e_n_t_a_g_e _u_s_e_d>,
               <_f_i_l_e _s_y_s_t_e_m _r_o_o_t>

       In the following list, all quantities expressed in 512-byte units
       (1024-byte when --kk is specified) shall be rounded up to the next higher
       unit. The fields are:

       <_f_i_l_e _s_y_s_t_e_m _n_a_m_e>
                 The name of the file system, in an implementation-defined
                 format.

       <_t_o_t_a_l _s_p_a_c_e>
                 The total size of the file system in 512-byte units. The
                 exact meaning of this figure is implementation-defined, but
                 should include <_s_p_a_c_e _u_s_e_d>, <_s_p_a_c_e _f_r_e_e>, plus any space
                 reserved by the system not normally available to a user.

       <_s_p_a_c_e _u_s_e_d>
                 The total amount of space allocated to existing files in the
                 file system, in 512-byte units.

       <_s_p_a_c_e _f_r_e_e>
                 The total amount of space available within the file system
                 for the creation of new files by unprivileged users, in
                 512-byte units. When this figure is less than or equal to
                 zero, it shall not be possible to create any new files on the
                 file system without first deleting others, unless the process
                 has appropriate privileges. The figure written may be less
                 than zero.

       <_p_e_r_c_e_n_t_a_g_e _u_s_e_d>
                 The percentage of the normally available space that is
                 currently allocated to all files on the file system. This
                 shall be calculated using the fraction:


                     <_s_p_a_c_e _u_s_e_d>/( <_s_p_a_c_e _u_s_e_d>+ <_s_p_a_c_e _f_r_e_e>)

                 expressed as a percentage. This percentage may be greater
                 than 100 if <_s_p_a_c_e _f_r_e_e> is less than zero. The percentage
                 value shall be expressed as a positive integer, with any
                 fractional result causing it to be rounded to the next
                 highest integer.

       <_f_i_l_e _s_y_s_t_e_m _r_o_o_t>
                 The directory below which the file system hierarchy appears.

       The output format is unspecified when --tt is used.

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
       On most systems, the ``name of the file system, in an implementation-
       defined format'' is the special file on which the file system is
       mounted.

       On large file systems, the calculation specified for percentage used
       can create huge rounding errors.

EEXXAAMMPPLLEESS
        1. The following example writes portable information about the //uussrr
           file system:


               df -P /usr

        2. Assuming that //uussrr//ssrrcc is part of the //uussrr file system, the
           following produces the same output as the previous example:


               df -P /usr/src

RRAATTIIOONNAALLEE
       The behavior of _d_f with the --PP option is the default action of the 4.2
       BSD _d_f utility. The uppercase --PP was selected to avoid collision with a
       known industry extension using --pp.

       Historical _d_f implementations vary considerably in their default
       output. It was therefore necessary to describe the default output in a
       loose manner to accommodate all known historical implementations and to
       add a portable option (--PP) to provide information in a portable format.

       The use of 512-byte units is historical practice and maintains
       compatibility with _l_s and other utilities in this volume of
       POSIX.1-2017. This does not mandate that the file system itself be
       based on 512-byte blocks. The --kk option was added as a compromise
       measure. It was agreed by the standard developers that 512 bytes was
       the best default unit because of its complete historical consistency on
       System V (_v_e_r_s_u_s the mixed 512/1024-byte usage on BSD systems), and
       that a --kk option to switch to 1024-byte units was a good compromise.
       Users who prefer the more logical 1024-byte quantity can easily alias
       _d_f to _d_f --kk without breaking many historical scripts relying on the
       512-byte units.

       It was suggested that _d_f and the various related utilities be modified
       to access a _B_L_O_C_K_S_I_Z_E environment variable to achieve consistency and
       user acceptance. Since this is not historical practice on any system,
       it is left as a possible area for system extensions and will be re-
       evaluated in a future version if it is widely implemented.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _f_i_n_d

       The Base Definitions volume of POSIX.1-2017, _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, _S_e_c_t_i_o_n _1_2_._2, _U_t_i_l_i_t_y _S_y_n_t_a_x _G_u_i_d_e_l_i_n_e_s

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                                DF(1)
