dh − debhelper command sequencer
dh sequence [−−with addon[,addon,...]] [−−list] [−−until cmd] [−−before cmd] [−−after cmd] [−−remaining] [debhelper options]
dh runs a sequence of debhelper commands. The supported sequences correspond to the targets of a debian/rules file: "build", "clean", "install", "binary-arch", "binary-indep", and "binary".
Commands in the binary-indep sequence are passed the "−i" option to ensure they only work on binary independent packages, and commands in the binary-arch sequences are passed the "−a" option to ensure they only work on architecture dependent packages.
If debian/rules contains a target with a name like "override_dh_command", then when it would normally run dh_command, dh will instead call that target. The override target can then run the command with additional options, or run entirely different commands instead. See examples below. (Note that to use this feature, you should Build-Depend on debhelper 7.0.50 or above.)
Add the debhelper commands specified by the given addon to appropriate places in the sequence of commands that is run. This option can be repeated more than once, or multiple addons can be listed, separated by commas. This is used when there is a third-party package that provides debhelper commands. See the PROGRAMMING file for documentation about the sequence addon interface.
The inverse of −−with, disables using the given addon.
List all available addons.
Run commands in the sequence until and including cmd, then stop.
Run commands in the sequence before cmd, then stop.
Run commands in the sequence that come after cmd.
Run all commands in the sequence that have yet to be run.
Prints commands that would run for a given sequence, but does not run them.
All other options passed to dh are passed on to each command it runs. This can be used to set an option like "−v" or "−X" or "−N", as well as for more specialised options.
In the above options, cmd can be a full name of a debhelper command, or a substring. It’ll first search for a command in the sequence exactly matching the name, to avoid any ambiguity. If there are multiple substring matches, the last one in the sequence will be used.
To see what commands are included in a sequence, without actually doing anything:
dh binary−arch −−no−act
This is a very simple rules file, for packages where the default sequences of commands work with no additional options.
#!/usr/bin/make −f %: dh $@
Often you’ll want to pass an option to a specific debhelper command. The easy way to do with is by adding an override target for that command.
#!/usr/bin/make −f %: dh $@ override_dh_strip: dh_strip −Xfoo override_dh_installdocs: dh_installdocs README TODO
#!/usr/bin/make −f %: dh $@ override_dh_auto_configure: ./mondoconfig override_dh_auto_build: make universe−explode−in−delight
Another common case is wanting to do something manually before or after a particular debhelper command is run.
#!/usr/bin/make −f %: dh $@ override_dh_fixperms: dh_fixperms chmod 4755 debian/foo/usr/bin/foo
If your package is a python package, dh will use dh_pysupport by default. This is how to use dh_pycentral instead.
#!/usr/bin/make −f %: dh $@ −−with python−central
If your package uses autotools and you want to freshen config.sub and config.guess with newer versions from the autotools-dev package at build time, you can use some commands provided in autotools-dev that automate it, like this.
#!/usr/bin/make −f %: dh $@ −−with autotools_dev
Here is how to force use of perl’s Module::Build build system, which can be necessary if debhelper wrongly detects that the package uses MakeMaker.
#!/usr/bin/make −f %: dh $@ −−buildsystem=perl_build
To patch your package using quilt, you can tell dh to use quilt’s dh sequence addons like this:
#!/usr/bin/make −f %: dh $@ −−with quilt
Here is an example of overriding where the dh_auto_* commands find the package’s source, for a package where the source is located in a subdirectory.
#!/usr/bin/make −f %: dh $@ −−sourcedirectory=src
And here is an example of how to tell the dh_auto_* commands to build in a subdirectory, which will be removed on clean.
#!/usr/bin/make −f %: dh $@ −−builddirectory=build
If your package can be built in parallel, you can support parallel building as follows. Then dpkg-buildpackage −j will work.
#!/usr/bin/make −f %: dh $@ −−parallel
Here is a way to prevent dh from running several commands that you don’t want it to run, by defining empty override targets for each command.
#!/usr/bin/make −f %: dh $@ # Commands not to run: override_dh_auto_test override_dh_compress override_dh_fixperms:
Sometimes, you may need to make an override target only run commands when a particular package is being built. This can be accomplished using dh_listpackages(1) to test what is being built. For example:
#!/usr/bin/make −f %: dh $@ override_dh_fixperms: dh_fixperms ifneq (,$(findstring foo, $(shell dh_listpackages))) chmod 4755 debian/foo/usr/bin/foo endif
Finally, remember that you are not limited to using override targets in the rules file when using dh. You can also explicitly define any of the regular rules file targets when it makes sense to do so. A common reason to do this is if your package needs different build-arch and build-indep targets. For example, a package with a long document build process can put it in build-indep to avoid build daemons redundantly building the documentation.
#!/usr/bin/make −f %: dh $@ build: build−arch build−indep ; build−indep: $(MAKE) docs build−arch: $(MAKE) bins
If you’re curious about dh’s internals, here’s how it works under the hood.
Each debhelper command will record when it’s successfully run in debian/package.debhelper.log. (Which dh_clean deletes.) So dh can tell which commands have already been run, for which packages, and skip running those commands again.
Each time dh is run, it examines the log, and finds the last logged command that is in the specified sequence. It then continues with the next command in the sequence. The −−until, −−before, −−after, and −−remaining options can override this behavior.
dh uses the DH_INTERNAL_OPTIONS environment variable to pass information through to debhelper commands that are run inside override targets. The contents (and indeed, existence) of this environment variable, as the name might suggest, is subject to change at any time.
This program is a part of debhelper.
Joey Hess <joeyh [AT] debian.org>