(This file does not appear in release tarballs.) In a release or snapshot tarball of PostgreSQL, a documentation file named INSTALL will appear in this directory. However, this file is not stored in git and so will not be present if you are using a git checkout. If you are using a git checkout, you can view the most recent installation instructions at: https://www.postgresql.org/docs/devel/installation.html Users compiling from git will also need compatible versions of Bison, Flex, and Perl, as discussed in the install documentation. These programs are not needed when using a tarball, since the files they are needed to build are already present in the tarball. (On Windows, however, you need Perl anyway.)