SYNOPSIS
       envsubst [OPTION] [SHELL-FORMAT]

DESCRIPTION
       Substitutes the values of environment variables.

   Operation mode:
       -v, --variables
              output the variables occurring in SHELL-FORMAT

   Informative output:
       -h, --help
              display this help and exit

       -V, --version
              output version information and exit

       In  normal operation mode, standard input is copied to standard output,
       with references to environment  variables  of  the  form  $VARIABLE  or
       ${VARIABLE}  being replaced with the corresponding values.  If a SHELL-
       FORMAT is given, only those environment variables that  are  referenced
       in  SHELL-FORMAT  are  substituted; otherwise all environment variables
       references occurring in standard input are substituted.

       When --variables is used, standard input is  ignored,  and  the  output
       consists of the environment variables that are referenced in SHELL-FOR-
       MAT, one per line.

AUTHOR
       Written by Bruno Haible.

REPORTING BUGS
       Report bugs to <bug-gnu-gettext@gnu.org>.

COPYRIGHT
       Copyright (C) 2003-2007 Free Software Foundation, Inc.  License GPLv3+:
       GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
       This  is  free  software:  you  are free to change and redistribute it.
       There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
       The full documentation for envsubst is maintained as a Texinfo  manual.
       If  the info and envsubst programs are properly installed at your site,
       the command

              info envsubst

       should give you access to the complete manual.