Tags

Tags are a central concept in HermitGrab. Each action (link, patch, install) can require the presence or absence of specific tags. Actions are enabled or disabled based on the set of active tags.

There are multiple sources for tags.

The command line

When running the apply command, you can specify multiple tags with the -tor --tag argument.

A profile

Instead of specifying tags individually on the command line, you can create a profile, which is a collection of tags. When the -p or --profile argument is used, all tags in that profile become active. If no profile is specified, the default profile is used if it has been defined.

Built-in Auto-detected Tags

HermitGrab automatically detects system information and provides it as tags. For example:

• arch=aarch64 (possible Values)
• arch_alias=arm64 (Either arm64, amd64, armhf or the same as arch=)
• hostname=b8346a603af8
• os=linux (possible Values)
• os_bitness=64
• os_codename=bookworm
• os_family=unix (possible Values)
• os_version=12.0.0
• user=vscode

These are particularly useful for ensuring that tools are only installed on compatible platforms. For example, a configuration file for the Fish shell, which is not available on Windows, might include the following requires key:

requires = ["fish", "+os_family=unix"]

Custom Tag Detectors

You can also define custom tags based on the output of a script. For example:

[detectors]
# The `k9s` tag is activated if the command returns a successful exit code.
k9s = { enable_if = "command -v kubectl" }
# The `is_container` tag is activated if the command returns a non-zero exit code.
is_container = { enable_if_not = "grep -q 'systemd' /proc/1/cmdline" }
# Upon successful execution, the command's standard output is used to set a tag's value,
# for example `shell=/bin/bash`.
shell = { value_of = "echo $SHELL" }