NAME

       deb-substvars - Debian source substitution variables

SYNOPSIS

       substvars

DESCRIPTION

       Before  dpkg-source,  dpkg-gencontrol  and dpkg-genchanges write their control information
       (to  the  source  control  file  .dsc  for  dpkg-source  and  to   standard   output   for
       dpkg-gencontrol  and  dpkg-genchanges)  they  perform  some  variable substitutions on the
       output file.

       A variable  substitution  has  the  form  ${variable-name}.   Variable  names  consist  of
       alphanumerics,  hyphens  and colons and start with an alphanumeric. Variable substitutions
       are performed repeatedly until none are left;  the  full  text  of  the  field  after  the
       substitution is rescanned to look for more substitutions.

       After all the substitutions have been done each occurrence of the string ${} (which is not
       a legal substitution) is replaced with a $ sign.

       While variable substitution is done on all control fields, some of those fields  are  used
       and  needed during the build when the substitution did not yet occur. That's why you can't
       use variables in the Package, Source and Architecture fields.

       Variable substitution happens on the content of the fields after they  have  been  parsed,
       thus  if  you  want  a variable to expand over multiple lines you do not have to include a
       space after the newline. This is done implicitly when the field is output. For example, if
       the variable ${Description} is set to "foo is bar.${Newline}foo is great." and if you have
       the following field:

        Description: foo application
         ${Description}
         .
         More text.

       It will result in:

        Description: foo application
         foo is bar.
         foo is great.
         .
         More text.

       Variables can be set using the -V common option. They can be also specified  in  the  file
       debian/substvars  (or  whatever  other  file  is specified using the -T option). This file
       consists of lines of the form name=value.  Trailing whitespace on each line, blank  lines,
       and lines starting with a # symbol (comments) are ignored.

       Additionally, the following standard variables are available:

       Arch   The  current  host  architecture  (i.e. the architecture the package is being built
              for, the equivalent of DEB_HOST_ARCH).

       source:Version
              The source package version.

       source:Upstream-Version
              The upstream source package version, including the Debian version epoch if any.

       binary:Version
              The binary package version (which may differ from source:Version in  a  binNMU  for
              example).

       Source-Version
              The  source  package  version  (from  the  changelog  file).  This  variable is now
              deprecated  as  its  meaning  is  different  from  its  function,  please  use  the
              source:Version or binary:Version as appropriate.

       Installed-Size
              The  approximate  total size of the package's installed files. This value is copied
              into the corresponding control file field; setting it will modify the value of that
              field.  If  this variable is not set dpkg-gencontrol will compute the default value
              by accumulating the size of each regular file and symlink rounded  to  1  KiB  used
              units, and a baseline of 1 KiB for any other filesystem object type.

              Note:  Take into account that this can only ever be an approximation, as the actual
              size used on the installed system will depend greatly on the  filesystem  used  and
              its  parameters,  which  might  end  up  using  either  more or less space than the
              specified in this field.

       Extra-Size
              Additional disk space used when the package is installed. If this variable  is  set
              its  value  is added to that of the Installed-Size variable (whether set explicitly
              or using the default value) before it is copied  into  the  Installed-Size  control
              file field.

       F:fieldname
              The  value  of  the  output  field  fieldname (which must be given in the canonical
              capitalisation). Setting these variables has no effect other than on  places  where
              they are expanded explicitly.

       Format The  .changes file format version generated by this version of the source packaging
              scripts. If you set this variable the contents of the Format field in the  .changes
              file will change too.

       Newline, Space, Tab
              These variables each hold the corresponding character.

       shlibs:dependencyfield
              Variable settings with names of this form are generated by dpkg-shlibdeps.

       dpkg:Upstream-Version
              The upstream version of dpkg.

       dpkg:Version
              The full version of dpkg.

       If  a variable is referred to but not defined it generates a warning and an empty value is
       assumed.

FILES

       debian/substvars
              List of substitution variables and values.

SEE ALSO

       dpkg(1), dpkg-genchanges(1), dpkg-gencontrol(1), dpkg-shlibdeps(1), dpkg-source(1).