Provided by: dpkg-dev_1.21.9ubuntu1_all 
NAME
deb-substvars - Debian source substitution variables
SYNOPSIS
debian/substvars, debian/binary-package.substvars, variables
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.
Variable Syntax
A variable substitution has the form ${variable-name}. Variable names consist of
alphanumerics (a-zA-Z0-9), hyphens (-) and colons (:) and start with an alphanumeric, and
are case-sensitive, even though they might refer to other entities which are case-
preserving. 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.
File Syntax
Substitution variables can be specified in a file. These files consist of lines of the
form name=value or name?=value. The = operator assigns a normal substitution variable,
while the ?= operator (since dpkg 1.21.8) assigns an optional substitution variable which
will emit no warnings even if unused. Trailing whitespace on each line, blank lines, and
lines starting with a # symbol (comments) are ignored.
Substitution
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 common option).
After all the substitutions have been done each occurrence of the string ${} (which is not
an actual substitution variable) is replaced with a $ sign. This can be used as an escape
sequence such as ${}{VARIABLE} which will end up as ${VARIABLE} on the output.
If a variable is referred to but not defined it generates a warning and an empty value is
assumed.
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.
Built-in Variable
Additionally, the following standard variables are always available:
Arch
The current host architecture (i.e. the architecture the package is being built for,
the equivalent of DEB_HOST_ARCH).
vendor:Name
The current vendor name (since dpkg 1.20.0). This value comes from the Vendor field
for the current vendor's origin file, as dpkg-vendor(1) would retrieve it.
vendor:Id
The current vendor ID (since dpkg 1.20.0). This is just the lowercase variant of
vendor:Name.
source:Version
The source package version (since dpkg 1.13.19).
source:Upstream-Version
The upstream source package version, including the Debian version epoch if any (since
dpkg 1.13.19).
binary:Version
The binary package version (which may differ from source:Version in a binNMU for
example; since dpkg 1.13.19).
Source-Version
The source package version (from the changelog file). This variable is now obsolete
and emits an error when used as its meaning is different from its function, please use
the source:Version or binary:Version as appropriate.
source:Synopsis
The source package synopsis, extracted from the source stanza Description field, if it
exists (since dpkg 1.19.0).
source:Extended-Description
The source package extended description, extracted from the source stanza Description
field, if it exists (since dpkg 1.19.0).
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. With hardlinks only
being counted once as a regular file.
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.
S:fieldname
The value of the source stanza field fieldname (which must be given in the canonical
capitalisation; since dpkg 1.18.11). Setting these variables has no effect other than
on places where they are expanded explicitly. These variables are only available when
generating binary control files.
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 (since dpkg 1.13.19).
dpkg:Version
The full version of dpkg (since dpkg 1.13.19).
FILES
debian/substvars
List of substitution variables and values.
SEE ALSO
dpkg(1), dpkg-vendor(1), dpkg-genchanges(1), dpkg-gencontrol(1), dpkg-shlibdeps(1), dpkg-
source(1).