Afio archiver home page

This is the home page for the afio archiver program for Linux/UNIX.

Afio makes cpio-format archives. It deals somewhat gracefully with input data corruption, supports multi-volume archives during interactive operation, and can make compressed archives that are much safer than compressed tar or cpio archives. Afio is best used as an `archive engine' in a backup script.

The latest version is 2.5.2, released in 2018. This announce message describes the major changes.

Afio is free/open source software. As an open source project, it is somewhat peculiar because it is over 30 years old.

Getting Afio

  1. If your Linux is Debian or Debian-based, you can try
    sudo apt-get install afio

  2. Or you can compile afio from source. The latest source release is at See the INSTALLATION file in the source release for instructions. If you are impatient, pasting this to a terminal may work:
    tar zxf afio-2.5.2.tgz
    cd afio-2.5.2
    sudo make install
There is no guarantee that these two methods will get you exactly the same version of afio. In general, the Debian package maintainers and me as the upstream project maintainer try to keep things in sync, but we all have limited time. If you run afio without any command line arguments it will print its version number.

Useful links

Reporting problems, questions, bugs, submitting patches, etc

There are many options.

Maintenance status

Afio is now in a 'maintenance only' mode, with several years between formal releases. 'Maintenance only' means that I will be happy to answer questions, to handle bug and problem reports, and to incorporate patches that fix bugs, portabiliy problems, and security issues. However, it is very unlikely that I will work on adding major new features, even if the feature request comes with a patch file implementing the feature.

The main concern that drives my maintenance policy is to avoid creating new bugs that would cause the backup process to silently fail. Because of this concern, I do a lot of manual reviewing and testing for every patch I receive. I have concluded that I simply do not have the time (and interest level) anymore to do this for patches adding new features. My interest has declined because since about 2005, hard drives have become so cheap that making fault tolerant compressed archive files for writing to tapes of floppy disks, as afio can do, has become less and less relevant to the needs of average Linux user. I make my personal system backups using rsync on a detachable hard drive.

When to use Afio

Selecting a backup solution for Linux can be a problem. There are too many software solutions. Some of them are not maintained at all anymore. Many of them (including afio) are not maintained very actively.

My recommendation depends on what you want to do:

  1. You want to package some files together to put on a web site or in an e-mail.
    In this case, use a well-known archiver that everybody has installed by default, like tar or zip.

  2. You want to make a backup, and you have a removable or remote hard drive/flash drive with plenty of space.
    In this case, copy the entire filesystem tree you want to back up. You can use a file system copying tool like rsync, or a GUI tool that incorporates rsync.

  3. You want to make a backup to a compressed archive to save time/money/space.
    Typically this happens when backing up to CD/DVD/Blu-ray disks or tape. In this case:

Afio is also sometimes used together with pgp or gpg to make fault tolerant encrypted archives. Some people use it to archive unusual filesystems that have 100.000s of hard links or that have filenames with '\n' characters inside.

History and License

The original version of afio was written by Mark Brukhartz in 1985. He posted it to the comp.sources.unix USENET newsgroup in 1987. This newsgroup was an early distribution mechanism for free UNIX software. Since 1987, 100s of people have contributed to afio, and the afio code size has grown by a factor of 4. In 1992, the first Linux port of afio was uploaded to Sunsite, an early Linux FTP site. Koen Holtman became the afio maintainer in 1994 and has been so ever since. Afio attracted significant developer mindshare in the period 1992-2003 because it was the only open source archiver offering fault tolerant compression, which was important at the time for people making backups to floppies, tape drives, and later CDs. After 2003, development activity on afio slowed down a lot. This was partly because of software maturity, and partly because the lower cost of storage made compression less of an issue.

Afio has always been available for free. However, the original afio license written in 1985 (see afio.c) pre-dates modern open source licenses written with the help of actual lawyers. Around 2008, some people started to see this as a serious problem. There are two ways to look at the license:

If reading about this kind of license stuff is your idea of fun, here are some fun links.

Koen Holtman. Last updated November 2018.