apk-world(5)
/etc/apk/world - list of constraints for package selection
At /etc/apk/world, apk maintains the world, that is, a list of constraints the package selection needs to fulfill.
If you edit this file manually, you should run apk-fix(8) to apply the changes.
This is a plaintext file with one constraint using dependency notation per line. Each line has the format: name{@tag}{[<>~=]version}.
When modifying existing installation, the installed version is preferred unless an upgrade is requested or a world constraint or package dependency requires an alternate version.
To enable selection from a tagged repository, use the format name@tag, e.g. busybox@edge. See apk-repositories(5) for details on tagged package repositories. Untagged repositories are also considered for constraints with a tag. The tag is inherited to all dependencies as an allowed repository. That is, the dependencies are selected from the tagged repository if the name@tag has a dependency with version constraint requiring a version available only from the tagged repository. If the dependency can be satisfied from non-tagged repository it will be preferred.
To constrain the acceptable versions of the package, use the =, <, >, >=, ~, >~ or <~ operators. Respectively, these require the package is equal to, less than, greater than, greater than or equal, prefix match, greater than or prefix match, or less than or prefix match to the specified version. The ~ operator constrains the package to the prefix match of the version number.
busybox Installs busybox from the untagged repository from which it is available.
busybox@edge Allows installation of busybox and it's dependencies from a repository tagged with "edge". Tagged repositories will not be prioritized. If a version from an untagged repository is a better fit it will be used.
busybox=1.6.1 Install busybox version 1.6.1.
busybox>1.6.1 Install a busybox version greater than 1.6.1.
busybox>=1.6.1 Install a busybox version greater than or equal to 1.6.1.
busybox<1.6.1 Install a busybox version less than 1.6.1.
busybox~1.6 Install any busybox version starting with 1.6. Examples of match: 1.6, 1.6.0_pre1, 1.6.0, 1.6.5, 1.6.9_p1.
busybox>~1.6 Install a busybox version greater than or prefix match of 1.6.
busybox<~1.6 Install a busybox version less than or prefix match of 1.6.