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Package management

This document describes how packages within a Hermit environment can be found, installed, and managed. Packages are defined in configuration files called manifests which are retrieved from collections of manifests called manifest sources which in turn are commonly (but not always) Git repositories.

Keeping up to Date

Hermit retrieves package manifests from various locations, including Git repositories. It will periodically sync these repositories to your system to ensure you have the most up to date manifests. Similarly, Hermit will periodically update itself and packages installed by channel. You can force this by running:

projectšŸš~/project$ hermit update

Searching for Packages

Search for packages with the search command, optionally passing a substring to match within the package name or description:

projectšŸš~/project$ hermit search rust
rust (@nightly, 1.51.0)
  A language empowering everyone to build reliable and efficient software.

Selecting Packages

Packages can be selected in one of three ways:

  1. By version - <package>-<version>

    A specific version of a package can be installed by specifying <package>-<version>. eg. hermit install rustc-1.51.0

  2. By channel - <package>@<channel>

    Channels can be explicitly selected with <package>@<channel>, eg. hermit install rustc@nightly. Channels are automatically updated at a frequency defined by the package manifest.

  3. By preferred version - <package>

    When specifying just a package name, ie. <package>, the preferred version will be installed. The preferred version is, in order of priority:

    1. The version specified as the default in the manifest.
    2. The latest stable version.
    3. The latest unstable version.
    4. The last channel, alphabetically.

Installing Packages

To install the latest stable version of protoc and the nightly channel of rust:

projectšŸš~/project$ hermit install rust@nightly protoc

At this point if you ls bin you will see something like the following:

projectšŸš~/project$ ls bin  clippy-driver@    rust-analyzer@    rustc@
activate-hermit*  hermit*           rust-demangler@   rustdoc@
cargo@            hermit.hcl        rust-gdb@
cargo-clippy@     miri@             rust-gdbgui@
cargo-miri@       protoc@           rust-lldb@

List Installed Packages

To list packages installed in the active environment:

projectšŸš~/project$ hermit list
protoc (3.14.0)
  protoc is a compiler for protocol buffers definitions files.
rust (@nightly)
  A language empowering everyone to build reliable and efficient software.

Package Information

You can obtain more detailed package information with hermit info <package>, eg.

projectšŸš~/project$ hermit info rust
hermit info rust@nightly
Name: rust
Channel: nightly
Description: A language empowering everyone to build reliable and efficient software.
State: installed
Last used: 3m36.889138s ago
Root: /home/user/.cache/hermit/pkg/rust@nightly
Binaries: cargo cargo-clippy clippy-driver cargo-miri miri rust-analyzer rust-demangler rust-gdb rust-gdbgui rust-lldb rustc rustdoc

Upgrading Packages

For package channels or versions that adhere to semantic versioning, Hermit will automatically upgrade to the latest minor version using the hermit upgrade command:

projectšŸš~/project$ hermit upgrade rust
projectšŸš~/project$ rustc --version
rustc 1.51.0 (2fd73fabe 2021-03-23)

Downgrading / Changing Versions

To downgrade or switch to a specific version, use hermit install to explicitly specify the version. eg.

projectšŸš~/project$ hermit install rust-1.50.0
projectšŸš~/project$ rustc --version
rustc 1.50.0 (940f2a77 2021-01-02)

Uninstalling Packages

Use hermit uninstall:

projectšŸš~/project$ hermit uninstall rust