# ACL2 Version 8.2 Installation Guide

# Easy Install for Unix-like Systems

Here, "Unix-like Systems" includes Unix, GNU-Linux, and MacOS X. Note that a quicker and even easier install may be possible, by instead obtaining a pre-built binary distribution if one is available for your platform. Otherwise, you can follow the directions below, which start by fetching a file hosted at the github ACL2 System and Books website. The result is a directory containing not only the ACL2 system but, in the `books/` subdirectory, the community books (libraries). The ACL2 system is developed at the University of Texas at Austin and can also be obtained or explored separately.

1. Connect to a directory whose full pathname contains no whitespace and which does not already contain a subdirectory named `acl2-sources` or `acl2-8.2`. Then use either of the following two methods to obtain the ACL2 source code and community books.
   - (Recommended if you don't plan to update from git)
     Fetch gzipped tar file `acl2-8.2.tar.gz` from GitHub and then execute:
     `tar xfz acl2-8.2.tar.gz`
     This will create a subdirectory named `acl2-8.2`. Connect to `acl2-8.2`.
   - (Development snapshot, required if you want to update from GitHub: generally should be fine, but on rare occasions may be incomplete, fragile, or unable to pass the usual regression tests)
     Execute:
     `git clone https://github.com/acl2/acl2 acl2-sources`
     This will create the subdirectory `acl2-sources`. Connect to `acl2-sources/`.

2. Obtain a Common Lisp implementation if you don't already have one.

3. Type:

       make LISP=<path_to_your_lisp_executable>

   This will create a script in your connected directory for running ACL2. The script is named `saved_acl2`.
   Note: You will need Gnu make. We have seen problems on some Linux systems with Version 3.81 of that utility, so if you encounter errors, please consider our instructions for downloading and installing GNU make version 3.80.

4. Certify books, for example with

       make

   or something fancier such as the following:

       (time nice make -j 8 ACL2=/u/smith/bin/acl2 basic) >& make-basic.log

   This may take only a few minutes, depending your `-j` value, your machine, and your host Common Lisp. The resulting log should contain no occurrences of the string ``CERTIFICATION FAILED''; a normal exit (status 0) should guarantee this. If you want additional explanation and further options (e.g., about perhaps avoiding root login), see the documentation for BOOKS-CERTIFICATION.

You now have an ACL2 executable called `saved_acl2` (from step 3) and access to certified community books (from step 4). Enjoy!

THE ABOVE INSTRUCTIONS MAY BE ALL THAT YOU NEED. Otherwise, read on....

# More Information

- REQUIREMENTS
  - Performance comparisons
  - Obtaining Common Lisp
- OBTAINING AND INSTALLING ACL2
  - Pre-built Binary Distributions
  - Obtaining the Sources
  - Creating or Obtaining an Executable Image
  - Running Without Building an Executable Image
  - Summary of Distribution
- USING ACL2
  - Invoking ACL2
    - When ACL2 Starts Up
  - Testing ACL2
  - Certifying ACL2 Books
  - Documentation
  - Emacs
- MISCELLANEOUS INFORMATION
  - Problems
  - Reasoning about the Real Numbers
  - Links and Mailing Lists
  - Export/Re-Export Limitations
  - License and Copyright

Note: To build variants of ACL2, see the documentation topic REAL for ACL2(r) and COMPILING-ACL2P for ACL2(p).