LOGGER(1)                  POSIX Programmer's Manual                 LOGGER(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
       logger -- log messages

SSYYNNOOPPSSIISS
       logger _s_t_r_i_n_g...

DDEESSCCRRIIPPTTIIOONN
       The _l_o_g_g_e_r utility saves a message, in an unspecified manner and
       format, containing the _s_t_r_i_n_g operands provided by the user. The
       messages are expected to be evaluated later by personnel performing
       system administration tasks.

       It is implementation-defined whether messages written in locales other
       than the POSIX locale are effective.

OOPPTTIIOONNSS
       None.

OOPPEERRAANNDDSS
       The following operand shall be supported:

       _s_t_r_i_n_g    One of the string arguments whose contents are concatenated
                 together, in the order specified, separated by single <space>
                 characters.

SSTTDDIINN
       Not used.

IINNPPUUTT FFIILLEESS
       None.

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

       _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. (This means diagnostics from _l_o_g_g_e_r to the user or
                 application, not diagnostic messages that the user is sending
                 to the system administrator.)

       _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
       Not used.

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

OOUUTTPPUUTT FFIILLEESS
       Unspecified.

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
       This utility allows logging of information for later use by a system
       administrator or programmer in determining why non-interactive
       utilities have failed. The locations of the saved messages, their
       format, and retention period are all unspecified. There is no method
       for a conforming application to read messages, once written.

EEXXAAMMPPLLEESS
       A batch application, running non-interactively, tries to read a
       configuration file and fails; it may attempt to notify the system
       administrator with:


           logger myname: unable to read file foo. [timestamp]

RRAATTIIOONNAALLEE
       The standard developers believed strongly that some method of alerting
       administrators to errors was necessary. The obvious example is a batch
       utility, running non-interactively, that is unable to read its
       configuration files or that is unable to create or write its results
       file. However, the standard developers did not wish to define the
       format or delivery mechanisms as they have historically been (and will
       probably continue to be) very system-specific, as well as involving
       functionality clearly outside the scope of this volume of POSIX.1-2017.

       The text with _L_C___M_E_S_S_A_G_E_S about diagnostic messages means diagnostics
       from _l_o_g_g_e_r to the user or application, not diagnostic messages that
       the user is sending to the system administrator.

       Multiple _s_t_r_i_n_g arguments are allowed, similar to _e_c_h_o, for ease-of-
       use.

       Like the utilities _m_a_i_l_x and _l_p, _l_o_g_g_e_r is admittedly difficult to
       test. This was not deemed sufficient justification to exclude these
       utilities from this volume of POSIX.1-2017. It is also arguable that
       they are, in fact, testable, but that the tests themselves are not
       portable.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _l_p, _m_a_i_l_x, _w_r_i_t_e

       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

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                            LOGGER(1)
