autoconf is a tool for producing shell scripts that automatically configure software source code packages to adapt to many kinds of Unix-like systems. The configuration scripts it produces are independent -- running them does not require the autoconf program. autoheader is a tool for creating template files of C #define statements for configure to use. autom4te is a wrapper for the M4 macro processor. autoreconf comes in handy when there are a lot of autoconf-generated configure scripts around. The program runs autoconf and autoheader repeatedly (where appropriate) to remake the autoconf configure scripts and configuration header templates in a given directory tree. autoscan can help to create a configure.in file for a software package. It examines the source files in a directory tree, searching them for common portability problems and creates a configure.scan file that serves as as a preliminary configure.in for the package. autoupdate modifies a configure.in file that still calls autoconf macros by their old names to use the current macro names. ifnames can be helpful when writing a configure.in for a software package. It prints the identifiers that the package uses in C preprocessor conditionals. If a package has already been set up to have some portability, this program can help to determine what configure needs to check. It can fill in some gaps in a configure.in file generated by autoscan.