FG(1)                      POSIX Programmer's Manual                     FG(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
       fg -- run jobs in the foreground

SSYYNNOOPPSSIISS
       fg [[_j_o_b___i_d]]

DDEESSCCRRIIPPTTIIOONN
       If job control is enabled (see the description of _s_e_t --mm), the _f_g
       utility shall move a background job from the current environment (see
       _S_e_c_t_i_o_n _2_._1_2, _S_h_e_l_l _E_x_e_c_u_t_i_o_n _E_n_v_i_r_o_n_m_e_n_t) into the foreground.

       Using _f_g to place a job into the foreground shall remove its process ID
       from the list of those ``known in the current shell execution
       environment''; see _S_e_c_t_i_o_n _2_._9_._3_._1, _E_x_a_m_p_l_e_s.

OOPPTTIIOONNSS
       None.

OOPPEERRAANNDDSS
       The following operand shall be supported:

       _j_o_b___i_d    Specify the job to be run as a foreground job. If no _j_o_b___i_d
                 operand is given, the _j_o_b___i_d for the job that was most
                 recently suspended, placed in the background, or run as a
                 background job shall be used. The format of _j_o_b___i_d is
                 described in the Base Definitions volume of POSIX.1-2017,
                 _S_e_c_t_i_o_n _3_._2_0_4, _J_o_b _C_o_n_t_r_o_l _J_o_b _I_D.

SSTTDDIINN
       Not used.

IINNPPUUTT FFIILLEESS
       None.

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

       _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 _f_g utility shall write the command line of the job to standard
       output in the following format:


           "%s\n", <_c_o_m_m_a_n_d>

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
       If job control is disabled, the _f_g utility shall exit with an error and
       no job shall be placed in the foreground.

       _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 _f_g utility does not work as expected when it is operating in its
       own utility execution environment because that environment has no
       applicable jobs to manipulate. See the APPLICATION USAGE section for
       _b_g.  For this reason, _f_g is generally implemented as a shell regular
       built-in.

EEXXAAMMPPLLEESS
       None.

RRAATTIIOONNAALLEE
       The extensions to the shell specified in this volume of POSIX.1-2017
       have mostly been based on features provided by the KornShell. The job
       control features provided by _b_g, _f_g, and _j_o_b_s are also based on the
       KornShell. The standard developers examined the characteristics of the
       C shell versions of these utilities and found that differences exist.
       Despite widespread use of the C shell, the KornShell versions were
       selected for this volume of POSIX.1-2017 to maintain a degree of
       uniformity with the rest of the KornShell features selected (such as
       the very popular command line editing features).

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _S_e_c_t_i_o_n _2_._9_._3_._1, _E_x_a_m_p_l_e_s, _S_e_c_t_i_o_n _2_._1_2, _S_h_e_l_l _E_x_e_c_u_t_i_o_n _E_n_v_i_r_o_n_m_e_n_t,
       _b_g, _k_i_l_l, _j_o_b_s, _w_a_i_t

       The Base Definitions volume of POSIX.1-2017, _S_e_c_t_i_o_n _3_._2_0_4, _J_o_b _C_o_n_t_r_o_l
       _J_o_b _I_D, _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                                FG(1)
