# Install base91 with Homebrew, MacPorts, Nix

Utility to encode and decode base91 files. Version 0.6.0 via Homebrew; verified from local package data.

## Install

```sh
sudo av install brew:base91
```

Additional install commands:

### macOS

- Homebrew (100%):

```sh
brew install base91
```

  Evidence: local Homebrew formula metadata

- MacPorts (94%):

```sh
sudo port install base91
```

  Evidence: MacPorts ports tree: mail/base91/Portfile from https://api.github.com/repos/macports/macports-ports/git/trees/master?recursive=1

### Linux

- Nix (92%):

```sh
nix profile install nixpkgs#base91
```

  Evidence: nixpkgs package indexes: pkgs/by-name/ba/base91/package.nix from https://api.github.com/repos/NixOS/nixpkgs/git/trees/master?recursive=1

## Package facts

- **Package key:** brew:base91
- **Package manager:** Homebrew
- **Package manager page:** <https://formulae.brew.sh/formula/base91>
- **Version:** 0.6.0
- **Source summary:** Utility to encode and decode base91 files
- **Homepage:** <https://base91.sourceforge.net/>
- **Upstream docs:** <https://base91.sourceforge.net/>
- **License:** BSD-3-Clause
- **Source archive:** <https://downloads.sourceforge.net/project/base91/basE91/0.6.0/base91-0.6.0.tar.gz>
- **Generated:** 2026-07-08T07:18:31+00:00

## Executables

- b91dec (cli)
- b91enc (cli)
- base91 (cli)
- b91dec (alias)
- b91enc (alias)
- base91 (alias)

## Install behavior

- Post-install hook: not defined
- Bottle: available on arm64_big_sur, arm64_linux, arm64_monterey, arm64_sequoia, arm64_sonoma, arm64_tahoe, arm64_ventura, big_sur, catalina, monterey, sonoma, ventura

## Freshness

- Page generated: 2026-07-08
- Package-manager version: 0.6.0
- Local data: ok
- Upstream repository: https://base91.sourceforge.net/
- info: No package-manager update timestamp was available.
- info: Release/tag comparison is only available for GitHub repositories.
## Project history and usage

basE91 is a binary-to-text encoding method and command-line tool that encodes binary data as ASCII characters with less overhead than Base64 for many inputs.

### Project history

The SourceForge project page describes basE91 as an advanced method for encoding binary data as ASCII characters, similar to uuencode or Base64 but more efficient. It reports overhead of at most 23 percent and as low as 14 percent depending on input.

The SourceForge files page identifies the latest 0.6.0 Java archive release in November 2006, and the project page shows project activity dating to October 2006. The project's official website remains base91.sourceforge.net.

### Adoption history

basE91 remains niche, but the input package metadata lists Homebrew, MacPorts, and Nix packaging, and the SourceForge project records tens of thousands of file downloads over its lifetime. Its adoption is mostly among developers who specifically need denser ASCII armoring than Base64 rather than users of general-purpose OS tooling.

The project page classifies it under data formats, terminals, email, algorithms, and internet topics, reflecting the encoding's intended transport and storage use cases.

### How it is used

The packaged CLI exposes base91 plus b91enc and b91dec executables according to the Homebrew input metadata. It is used as an encoder/decoder filter for files or streams where ASCII-safe text output is required.

There is no documented configuration file or credentials store; the tool is a stateless encoder/decoder.

### Why package nerds care

basE91 is significant as one of the better-known post-Base64 ASCII-armoring experiments. It trades simplicity and universal support for denser output, which makes it a useful reference point in discussions of binary-to-text encoding efficiency.

Its package-manager presence is also a classic long-tail case: a 2006 SourceForge utility still appears in modern package indexes because encoding tools age slowly when their formats are stable.

### Timeline

- 2006: SourceForge project activity and project metadata date basE91 to October 2006.
- 2006: Latest SourceForge release path records version 0.6.0 in November 2006.
- 2020s: Input package metadata shows basE91 available through Homebrew, MacPorts, and Nix.

### Related projects

- Base64 and uuencode are the official comparison points named by the SourceForge description.
- Other ASCII-armoring and binary-to-text encodings, including Ascii85/Base85, are conceptually adjacent even though they are separate formats.
- SourceForge hosts the original project site and release files for basE91.

### Sources

- <https://base91.sourceforge.net/>
- <https://sourceforge.net/projects/base91>
- <https://sourceforge.net/projects/base91/files/>
- source_facts.package-manager


## Security Notes

narrow executable package without higher-risk signals.

- **Geiger risk:** green / low
- narrow executable package without higher-risk signals

## Source Database Details

- **Source Database:** Homebrew formula API
- **Tap:** homebrew/core
- **Full Name:** base91
- **Version Scheme:** 0
- **Revision:** 0
- **Bottle Stable Root URL:** <https://ghcr.io/v2/homebrew/core>
- **Deprecated:** no
- **Disabled:** no
- **Keg Only:** no
- **URL Keys:** stable

## Other Package-Manager Records

- Nix - base91: normalized package name match | nixpkgs package indexes: pkgs/by-name/ba/base91/package.nix from https://api.github.com/repos/NixOS/nixpkgs/git/trees/master?recursive=1
- MacPorts - base91: normalized package name match | MacPorts ports tree: mail/base91/Portfile from https://api.github.com/repos/macports/macports-ports/git/trees/master?recursive=1


## Related links

- [Terminal utility packages](https://www.automicvault.com/pkg/terminal-utilities/) - Matched terminal and command-line workflow metadata.
- [Text processing packages](https://www.automicvault.com/pkg/text-processing-tools/) - Matched text, document, or structured-data processing metadata.
- [Networking and protocol packages](https://www.automicvault.com/pkg/networking-protocol-tools/) - Matched network, protocol, or remote-service metadata.
- [Database and data packages](https://www.automicvault.com/pkg/database-data-tools/) - Matched database, SQL, migration, or data-store metadata.
- [base16384](https://www.automicvault.com/pkg/brew/base16384/) - Package name indicates the same formula family.
- [eccodes](https://www.automicvault.com/pkg/brew/eccodes/) - Shares av.db curated category or tags: cli, data, data-formats, decoding, encoding.
- [cgns](https://www.automicvault.com/pkg/brew/cgns/) - Shares av.db curated category or tags: cli, data, data-format.
- [netcdf](https://www.automicvault.com/pkg/brew/netcdf/) - Shares av.db curated category or tags: cli, data, data-format.
- [netcdf-cxx](https://www.automicvault.com/pkg/brew/netcdf-cxx/) - Shares av.db curated category or tags: cli, data, data-format.
- [netcdf-fortran](https://www.automicvault.com/pkg/brew/netcdf-fortran/) - Shares av.db curated category or tags: cli, data, data-format.
- [osm-pbf](https://www.automicvault.com/pkg/brew/osm-pbf/) - Shares av.db curated category or tags: cli, data, data-format.
- [adios2](https://www.automicvault.com/pkg/brew/adios2/) - Shares av.db curated category or tags: cli, data.
- [alluxio](https://www.automicvault.com/pkg/brew/alluxio/) - Shares av.db curated category or tags: cli, data.

## Combined YAML source

View the package source record on GitHub. [combined/base91.yml](https://github.com/automic-vault/db/blob/main/combined/base91.yml)


## Sources

- Nucleus package database
- Geiger risk classifier
- package-page enrichment
- curated package history
- package version freshness
- av.db category and tag curation
- package relationship graph
- external package-manager database matches
- cross-ecosystem install command graph
