redux is top down software build tool similar to make but simpler and more reliable.

It implements and extends the redo concept somewhat sparsely described by DJ Bernstein.

I implemented a minimal set of redo tools some years ago and used them enough to become convinced that the idea was worthwhile. However, they needed to be better, sharper, and faster before they could replace Make in my toolbox, thus, this tool.

redux is written in Go and requires the Go compiler to be installed. Go can be fetched from the Go site or your favorite distribution channel.

Assuming Go is installed, the command:

$ go get github.com/gyepisam/redux/redux

will fetch, build and install redux into a $GOBIN directory. To complete the installation, run the command:

$ redux install 

which installs the associated links to the binary and the man pages in a related directory. By default, the links are created in the same directory as the executable, but this can be changed with the environment variable: $BINDIR.

The redux man page documentation can be installed separately with the command

$ redux install man

There are several options for where to install the manual pages. Please see 'redux help install' for details.

redux supports the following commands:

•  init -- Creates or reinitializes one or more redo root directories.
  

• ifchange -- Creates dependency on targets and ensure that targets are up to date.
• ifcreate -- Creates dependency on non-existence of targets.

•  redo -- Builds files atomically.
  

• install -- Installs links and manual pages

The install links command creates links for each of these commands so they can be invoked as:

• redo-init
• redo-ifchange
• redo-ifcreate
• redo

A redo based system must have a directory named .redo at the top level project directory.

It is created with the redo-init command, whose effects are idempotent.

The database contains file status and metadata. Its format is not specified, but it must be capable of supporting multiple readers and multiple writers (though not necessarily writing to the same sections). Redux implements a file based database and a null database. The current file based database is probably about the slowest. Fortunately, new databases can be easily plugged in.

In the redo system, there are three kinds of files.

• do files are scripts that build targets. In addition, they establish file dependencies by calling redo-ifcreate and redo-ifchange. do files are invoked by the redo commands directly and indirectly by redo-ifchange.

• target files are generated or otherwise composed, likely from other files, by do scripts

• static or source files are manually created/edited. They are tracked for changes, but are not generated. As such, they have no do files.

There are two kinds of dependencies

• ifchange denotes a relationship where a change in one file marks the other as out of date. A ifchange B implies that a change in B invalidates A. Change includes creation, modification or deletion.

• ifcreate denotes a dependency on the creation or deletion of a file. A ifcreate B implies that when B comes into existence or ceases to exist, A will be outdated.

Please see the individual command documentation for further details.

#Credits

redux is written by Gyepi Sam self-redux@gyepi.com.

The redo concept is DJ Bernstein's and is described here.

Thanks to Szabolcs Szasz, Mateusz Czapliński, and dontdieych for their requests, feedback, suggestions, ideas, and bug reports.

I am interested in any and all feedback on this software.