.\" Automatically generated by Pod::Man 4.10 (Pod::Simple 3.35) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. 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Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "DH 1" .TH DH 1 "2021-03-06" "13.3.3~bpo10+1" "Debhelper" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" dh \- debhelper command sequencer .SH "SYNOPSIS" .IX Header "SYNOPSIS" \&\fBdh\fR \fIsequence\fR [\fB\-\-with\fR \fIaddon\fR[\fB,\fR\fIaddon\fR ...]] [\fB\-\-list\fR] [\fIdebhelper options\fR] .SH "DESCRIPTION" .IX Header "DESCRIPTION" \&\fBdh\fR runs a sequence of debhelper commands. The supported \fIsequence\fRs correspond to the targets of a \fIdebian/rules\fR file: \fBbuild-arch\fR, \&\fBbuild-indep\fR, \fBbuild\fR, \fBclean\fR, \fBinstall-indep\fR, \fBinstall-arch\fR, \&\fBinstall\fR, \fBbinary-arch\fR, \fBbinary-indep\fR, and \fBbinary\fR. .SH "OVERRIDE AND HOOK TARGETS" .IX Header "OVERRIDE AND HOOK TARGETS" A \fIdebian/rules\fR file using \fBdh\fR can override the command that is run at any step in a sequence, by defining an override target. It is also possible to inject a command before or after any step without affecting the step itself. .SS "Injecting commands before or after a step" .IX Subsection "Injecting commands before or after a step" \&\fINote\fR: This feature requires debhelper 12.8 or later plus the package must use compatibility mode 10 or later. .PP To inject commands before \fIdh_command\fR, add a target named \&\fBexecute_before_\fR\fIdh_command\fR to the rules files. Similarly, if you want to inject commands after \fIdh_command\fR, add the target \&\fBexecute_after_\fR\fIdh_command\fR. Both targets can be used for the same \&\fIdh_command\fR and also even if the command is overridden (as described in \&\*(L"Overriding a command\*(R" below). .PP When these targets are defined, \fBdh\fR will call the targets respectively before or after it would invoke \fIdh_command\fR (or its override target). .SS "Overriding a command" .IX Subsection "Overriding a command" To override \fIdh_command\fR, add a target named \fBoverride_\fR\fIdh_command\fR to the rules file. When it would normally run \fIdh_command\fR, \fBdh\fR 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. .SS "Architecture dependent/independent override and hook targets" .IX Subsection "Architecture dependent/independent override and hook targets" The override and hook targets can also be defined to run only when building architecture dependent or architecture independent packages. Use targets with names like \fBoverride_\fR\fIdh_command\fR\fB\-arch\fR and \fBexecute_after\fR\fIdh_command\fR\fB\-indep\fR. .PP This feature is available since debhelper 8.9.7 (for override targets) and 12.8 (for hook targets). .SS "Completely empty targets" .IX Subsection "Completely empty targets" As a special optimization, \fBdh\fR will skip a target if it is completely empty. This is mostly useful for override targets, where the command will simply be skipped without the overhead of invoking a dummy target. .PP Note that the target has to be completely empty for this to work: .PP .Vb 3 \& # Skip dh_bar \- the good and optimized way \& # Some rationale for skipping dh_bar goes here \& override_dh_bar: \& \& \& # Skip dh_foo \- the slow way \& override_dh_foo: \& # Some rationale for skipping dh_foo goes here \& # (these comments causes a dummy target to be run) .Ve .SS "Verifying targets are picked up by dh" .IX Subsection "Verifying targets are picked up by dh" If you want to confirm that \fBdh\fR has seen an override or a hook target, you can use the following command as an example: .PP .Vb 6 \& $ dh binary \-\-no\-act | grep dh_install | head \-n5 \& dh_installdirs \& dh_install \& debian/rules execute_after_dh_install \& dh_installdocs \& dh_installchangelogs .Ve .PP The \fBdebian/rules execute_after_dh_install\fR in the output, which signals that \fBdh\fR registered a \fBexecute_after_dh_install\fR target and would run it directly after \fBdh_install\fR\|(1). .PP Note that \*(L"Completely empty targets\*(R" will be omitted in the listing above. This makes it a bit harder to spot as you are looking for the omission of a command name. But otherwise, the principle remains the same. .SS "Caveats with hook targets and makefile conditionals" .IX Subsection "Caveats with hook targets and makefile conditionals" If you choose to wrap a hook target in makefile conditionals, please be aware that \fBdh\fR computes all the hook targets a head of time and caches the result for that run. Furthermore, the conditionals will be invoked again when \fBdh\fR calls the hook target later and will assume the answer did not change. .PP The parsing and caching \fIoften\fR happens before \fBdh\fR knows whether it will build arch:any (\-a) or/and arch:all (\-i) packages, which can produce confusing results \- especially when \fBdh_listpackages\fR\|(1) is part of the conditional. .PP Most of the problems can be avoided by making the hook target unconditional and then have the \*(L"body\*(R" be partially or completely conditional. As an example: .PP .Vb 10 \& # SIMPLE: It is well\-defined what happens. The hook target \& # is always considered. The "maybe run this" bit is \& # conditional but dh_foo is definitely skipped. \& # \& # Note: The conditional is evaluated "twice" where its \& # influences what happens. Once when dh check which hook \& # targets exist and once when the override_dh_foo hook target \& # is run. If *either* times return false, "maybe run this" \& # is skipped. \& override_dh_foo: \& ifneq (...) \& maybe run this \& endif \& \& # SIMPLE: This is also well\-defined. The hook target is always \& # run and dh_bar is skipped. The "maybe run this" bit is \& # conditional as one might expect. \& # \& # Note: The conditional is still evaluated multiple times (in \& # different process each time). However, only the evaluation \& # that happens when the hook target is run influences what \& # happens. \& override_dh_bar: \& : # Dummy command to force the target to always be run \& ifneq (...) \& maybe run this \& endif \& \& \& # COMPLICATED: This case can be non\-trivial and have sharp edges. \& # Use at your own peril if dh_listpackages in the conditional. \& # \& # Here, either dh_baz is run normally OR "maybe run this" is run \& # instead. \& # \& # And it gets even more complicated to reason about if dh needs to \& # recurse into debian/rules because you have an "explicit" \& # standard target (e.g. a "build\-arch:" target separate from "%:"). \& ifneq (...) \& override_dh_baz: \& maybe run this \& endif .Ve .PP These recipes are also relevant for conditional dependency targets, which are often seen in a variant of the following example: .PP .Vb 5 \& COND_TASKS = \& ifneq (...) \& COND_TASKS += maybe\-run\-this \& endif \& ... \& \& maybe\-run\-this: \& ... \& \& # SIMPLE: It is well\-defined what happens. Either the \& # $(COND_TASKS) are skipped or run. \& # \& # Note: The conditional is evaluated "twice" where its \& # influences what happens. Once when dh check which hook \& # targets exist and once when the override_dh_foo hook target \& # is run. If *either* times return false, $(COND_TASKS) \& # is skipped. \& override_dh_foo: $(COND_TASKS) \& \& \& # SIMPLE: This is also well\-defined. The hook target is always \& # run and dh_bar is skipped. The $(COND_TASKS) bit is \& # conditional as one might expect. \& # \& # Note: The conditional is still evaluated multiple times (in \& # different process each time). However, only the evaluation \& # that happens when the hook target is run influences what \& # happens. \& override_dh_bar: $(COND_TASKS) \& : # Dummy command to force the target to always be run \& \& # COMPLICATED: This case can be non\-trivial and have sharp edges. \& # Use at your own peril if dh_listpackages in the conditional. \& # \& ifneq (...) \& override_dh_baz: $(COND_TASKS) \& endif .Ve .PP When in doubt, pick the relevant \fB\s-1SIMPLE\s0\fR case in the examples above that match your need. .SH "OPTIONS" .IX Header "OPTIONS" .IP "\fB\-\-with\fR \fIaddon\fR[\fB,\fR\fIaddon\fR ...]" 4 .IX Item "--with addon[,addon ...]" 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 \fI\s-1PROGRAMMING\s0\fR file for documentation about the sequence addon interface. .Sp A \fBBuild-Depends\fR relation on the package \fBdh\-sequence\-\fR\fIaddon\fR implies a \fB\-\-with\fR \fIaddon\fR. This avoids the need for an explicit \&\fB\-\-with\fR in \fIdebian/rules\fR that only duplicates what is already declared via the build dependencies in \fIdebian/control\fR. The relation can (since 12.5) be made optional via e.g. build-profiles. This enables you to easily disable an addon that is only useful with certain profiles (e.g. to facilitate bootstrapping). .Sp Since debhelper 12.5, addons can also be activated in \fBindep\fR\-only mode (via \fBBuild-Depends-Indep\fR) or \fBarch\fR\-only mode (via \&\fBBuild-Depends-Arch\fR). Such addons are only active in the particular sequence (e.g. \fBbinary-indep\fR) which simplifies dependency management for cross-builds. .Sp Please note that addons activated via \fBBuild-Depends-Indep\fR or \&\fBBuild-Depends-Arch\fR are subject to additional limitations to ensure the result is deterministic even when the addon is unavailable (e.g. during clean). This implies that some addons are incompatible with these restrictions and can only be used via \&\fBBuild-Depends\fR (or manually via \fIdebian/rules\fR). Currently, such addons can only add commands to sequences. .IP "\fB\-\-without\fR \fIaddon\fR" 4 .IX Item "--without addon" The inverse of \fB\-\-with\fR, disables using the given addon. This option can be repeated more than once, or multiple addons to disable can be listed, separated by commas. .IP "\fB\-\-list\fR, \fB\-l\fR" 4 .IX Item "--list, -l" List all available addons. .Sp When called only with this option, \fBdh\fR can be called from any directory (i.e. it does not need access to files from a source package). .IP "\fB\-\-no\-act\fR" 4 .IX Item "--no-act" Prints commands that would run for a given sequence, but does not run them. .Sp Note that dh normally skips running commands that it knows will do nothing. With \-\-no\-act, the full list of commands in a sequence is printed. .PP Other options passed to \fBdh\fR are passed on to each command it runs. This can be used to set an option like \fB\-v\fR or \fB\-X\fR or \fB\-N\fR, as well as for more specialised options. .SH "EXAMPLES" .IX Header "EXAMPLES" To see what commands are included in a sequence, without actually doing anything: .PP .Vb 1 \& dh binary\-arch \-\-no\-act .Ve .PP This is a very simple rules file, for packages where the default sequences of commands work with no additional options. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ .Ve .PP 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. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \& \& override_dh_strip: \& dh_strip \-Xfoo \& \& override_dh_auto_configure: \& dh_auto_configure \-\- \-\-with\-foo \-\-disable\-bar .Ve .PP Sometimes the automated \fBdh_auto_configure\fR\|(1) and \fBdh_auto_build\fR\|(1) can't guess what to do for a strange package. Here's how to avoid running either and instead run your own commands. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \& \& override_dh_auto_configure: \& ./mondoconfig \& \& override_dh_auto_build: \& make universe\-explode\-in\-delight .Ve .PP Another common case is wanting to do something manually before or after a particular debhelper command is run. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \& \& # Example assumes debhelper/12.8 and compat 10+ \& execute_after_dh_fixperms: \& chmod 4755 debian/foo/usr/bin/foo .Ve .PP If you are on an older debhelper or compatibility level, the above example would have to be written as. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \& \& # Older debhelper versions or using compat 9 or lower. \& override_dh_fixperms: \& dh_fixperms \& chmod 4755 debian/foo/usr/bin/foo .Ve .PP Python tools are not run by dh by default, due to the continual change in that area. Here is how to use \fBdh_python2\fR. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \-\-with python2 .Ve .PP Here is how to force use of Perl's \fBModule::Build\fR build system, which can be necessary if debhelper wrongly detects that the package uses MakeMaker. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \-\-buildsystem=perl_build .Ve .PP Here is an example of overriding where the \fBdh_auto_\fR\fI*\fR commands find the package's source, for a package where the source is located in a subdirectory. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \-\-sourcedirectory=src .Ve .PP And here is an example of how to tell the \fBdh_auto_\fR\fI*\fR commands to build in a subdirectory, which will be removed on \fBclean\fR. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \-\-builddirectory=build .Ve .PP If your package can be built in parallel, please either use compat 10 or pass \fB\-\-parallel\fR to dh. Then \fBdpkg-buildpackage \-j\fR will work. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \-\-parallel .Ve .PP If your package cannot be built reliably while using multiple threads, please pass \fB\-\-no\-parallel\fR to dh (or the relevant \fBdh_auto_\fR\fI*\fR command): .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \-\-no\-parallel .Ve .PP Here is a way to prevent \fBdh\fR from running several commands that you don't want it to run, by defining empty override targets for each command. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \& \& # Commands not to run: \& override_dh_auto_test override_dh_compress override_dh_fixperms: .Ve .PP A long build process for a separate documentation package can be separated out using architecture independent overrides. These will be skipped when running build-arch and binary-arch sequences. .PP .Vb 3 \& #!/usr/bin/make \-f \& %: \& dh $@ \& \& override_dh_auto_build\-indep: \& $(MAKE) \-C docs \& \& # No tests needed for docs \& override_dh_auto_test\-indep: \& \& override_dh_auto_install\-indep: \& $(MAKE) \-C docs install .Ve .PP Adding to the example above, suppose you need to chmod a file, but only when building the architecture dependent package, as it's not present when building only documentation. .PP .Vb 3 \& # Example assumes debhelper/12.8 and compat 10+ \& execute_after_dh_fixperms\-arch: \& chmod 4755 debian/foo/usr/bin/foo .Ve .SH "INTERNALS" .IX Header "INTERNALS" If you're curious about \fBdh\fR's internals, here's how it works under the hood. .PP In compat 10 (or later), \fBdh\fR creates a stamp file \&\fIdebian/debhelper\-build\-stamp\fR after the build step(s) are complete to avoid re-running them. It is possible to avoid the stamp file by passing \fB\-\-without=build\-stamp\fR to \fBdh\fR. This makes \*(L"no clean\*(R" builds behave more like what some people expect at the expense of possibly running the build and test twice (the second time as root or under \fBfakeroot\fR\|(1)). .PP Inside an override target, \fBdh_*\fR commands will create a log file \&\fIdebian/package.debhelper.log\fR to keep track of which packages the command(s) have been run for. These log files are then removed once the override target is complete. .PP In compat 9 or earlier, each debhelper command will record when it's successfully run in \fIdebian/package.debhelper.log\fR. (Which \&\fBdh_clean\fR deletes.) So \fBdh\fR can tell which commands have already been run, for which packages, and skip running those commands again. .PP Each time \fBdh\fR is run (in compat 9 or earlier), 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. .PP A sequence can also run dependent targets in debian/rules. For example, the \*(L"binary\*(R" sequence runs the \*(L"install\*(R" target. .PP \&\fBdh\fR uses the \fB\s-1DH_INTERNAL_OPTIONS\s0\fR 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. .PP Commands in the \fBbuild-indep\fR, \fBinstall-indep\fR and \fBbinary-indep\fR sequences are passed the \fB\-i\fR option to ensure they only work on architecture independent packages, and commands in the \fBbuild-arch\fR, \&\fBinstall-arch\fR and \fBbinary-arch\fR sequences are passed the \fB\-a\fR option to ensure they only work on architecture dependent packages. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBdebhelper\fR\|(7) .PP This program is a part of debhelper. .SH "AUTHOR" .IX Header "AUTHOR" Joey Hess