Build automation
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Stu -- Build Automation

This is Stu, a build tool in the spirit of Make, but with two features that set it apart:

  • Parametrized rules: Like GNU Make's '%' character, but there can be multiple parameters, and they have names. The syntax is '$NAME', where NAME can be any string.
  • Dynamic dependencies: The dependencies of a target can be generated dynamically. When a dependency is enclosed in square brackets, it means that that file is built and dependencies are read from within that file.

See this blog article for a motivation:

For documentation, compile and read the manpage, or go directly to:


  • Tip: Set "export STU_OPTIONS=-E" in your .bashrc file to get explanations of common error messages in Stu.

  • Version 2 is out: This contains backward-incompatible changes to the Stu 1 series. See 'MIGRATION' for a list. Most changes are safe, i.e., Stu will produce an error when an old construct is used. This is to make place for new features. The only non-safe new syntax is in quoting using " and ', which now work exactly like in the shell.

See the file 'NEWS' for more news.

Installation guide

Stu is written in C++11 for POSIX platforms. You should have no problem getting it to run on vanilla Linux and other POSIX-compliant platforms.

Design Considerations

The design considerations of Stu are:

  • Genericity: Being able to execute long, dynamic lists of identical commands should be easy. Many projects need to run many identical tasks only differing by individual parameters. This is the main motivation of Stu, and where virtually all other Make replacements fail. Most Make replacement force the user to write loops or similar constructs.
  • Generality: Don't focus on a particular use case such as compilation, but be a generic build tool. There are no built-in rules for compilation or other specific applications. Instead, allow use case-specific rules to be written in the Stu language itself. Most Make replacement tools instead focus on one specific use-case, making them unsuitable for general use.
  • Files are the central datatype. Everything is a file. You can think of Stu as "a declarative programming language in which all variables are files." For instance, Stu has no variables like Make; instead, files are used. Other Make replacements are even worse than Make in this regard, and allow any variable in whatever programming language they are using. Stu is based on the Unix principle that any persistent object should have a name in the file system -- "Everything is a file".
  • Scalability: Assume that projects are so large that you can't just clean and rebuild everything if there are build inconsistencies. Files are sacred; never make the user delete files in order to rebuild things.
  • Simplicity: Do one thing well. We don't include features such as file compression that can be achieved by other tools from within shell commands. List of files and dependencies are themselves targets that are built using shell commands, and therefore any external software can be used to define them, without any special support needed from Stu. Too many Make replacements try to "avoid the shell" and include every transformation possible into the tool, effectively amassing dozens of unnecessary dependencies, and creating an ad-hoc language much less well-defined, and let alone portable, than the shell.
  • Portability: Embrace POSIX as an underlying standard. Use the shell as the underlying command interpreter. Don't try to create a purportedly portable layer on top of it, as POSIX already is a portability layer. Also, don't try to create a new portable language for executing commands, as /bin/sh already is one. Furthermore, don't use fancy libraries or hip programming languages. Stu is written in plain C++11 with only standard libraries. Many other Make replacements are based on specific programming languages are their "base standard", effectively limiting their use to that language, and thus preventing projects to use multiple programming languages. Others even do worse and create their own mini-language, invariably less portable than the shell.
  • Reliability: Stu has extensive unit test coverage, with more than 500 tests. All published versions pass 100% of these tests. All language features and error paths are unit tested.
  • Stability: We follow Semantic Versioning ( in order to provide syntax and semantics that are stable over time. Stu files written now will still work in the future.
  • Familiarity: Stu follows the conventions of Make as much as possible, to make it easier to make the switch from Make to Stu. For instance, the options -j and -k work like in Make. Also, Stu source can be edited with syntax highlighting for the shell, as the syntaxes are very similar.

Comparison to Make

In addition to the properties described above, advantages of Stu over Make are:

  • Error messages are much better (Make has the dreaded "missing separator"); Stu gives full traces like a C compiler. If you get an error, you know which part of the Stu file to fix.
  • Stu has a proper tokenization pass, instead of Make's variable substitution syntax. This makes the whole language much more predictable.
  • Variables are not used; instead Stu encourages to put everything in files. This makes builds much faster: In a typical Makefile, a lot of program logic must be implemented used Make functions (because of a lack of dynamic dependencies), making a large piece of code being executed on each Make invocation, even if the variables have not changed.
  • Stu catches typical Makefile errors such as dependencies that where not built. Make cannot do this because the namespace for files is intermixed with namespace for phony targets. In Stu, both namespaces are separate (phony targets are called "transient targets" in Stu), and thus Stu can perform all checks properly.
  • Stu has better support for interrupting large builds. Make will often hang or leave processes running.
  • Stu avoids the "inner platform" antipattern present in Make, in which a lot of shell functionality is duplicated in Make functions. For instance, why are there text filtering functions in Make when the shell already has grep and other tools? That's because in Make, you cannot use shell commands to define dynamic dependencies, so Make evolved to have its own mini text filtering language. Instead, Stu allows and encourages all program logic to be implemented in ordinary rules, i.e. using a proper shell.
  • Stu supports additional types of dependencies which are essential in large, complex projects, such as persistent dependencies with the prefix -p, optional dependencies with -o, and trivial dependencies with -t. These can only be emulated partially with Make by using unwieldy constructs.

Use Stu

To use Stu, replace your 'Makefile' with a 'main.stu' file, and instead of calling 'make', call 'stu'.

The see an example of Stu used in a large data mining project, see the file 'main.stu' in the KONECT-Analysis project:


Stu was written to accommodate the Koblenz Network Collection project (KONECT - at the University of Koblenz-Landau. It is thus mainly used for large data mining projects, where it manages everything from acquiring data from the web, to performing experiments, to generating plots and compiling the resulting Latex papers. It is also used for compiling C/C++ code, and for generating tarballs.

The name "Stu" follows the precedents of Make replacements Cook and Bake in referring to kitchen-related verbs, and also honours the author of the original Unix Make, Stuart Feldman.

Stu was written in 2014/2015/2016 by Jérôme Kunegis at the University of Koblenz-Landau, with help from other contributors.

Stu is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Stu is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

For support, write to Jérôme Kunegis, or go to