versions/README.md

versions

58 SLOC.

versions checks a url, applies a couple regular expressions, sorts the results using vercmp and shsort, and returns a sorted list of version numbers for any package it knows about.

written for lix-os maintainers to check for new versions of packages. depending on how the package's versions are presented, it may only return a few of the most recent version numbers for the package, or it may return the entire version history.

because parsing and sorting versions using POSIX-compliant shell script can be a very slow operation, it caches the results of previous sorting operations and only recomputes the sorted version list if it appears the list of versions at the package url has changed.

all package configuration and cache files are kept in subdirectories of the pkg directory.

each package's url file is tab-delimited. it is formatted as follows:

<url> <pre regex> <post regex> <version regex>

• <url> is a url which contains a list of versions.

• <pre regex> is the pattern up to which the content at url will be discarded before beginning to look for matches for version regex.

• <post regex> is the pattern after which the content at url will be discarded before beginning to look for matches for version regex.

• <version regex> is a pattern containing a subgroup matching the version strings versions should return. there are some default version regexes defined in versions.sh. any of these can be referenced in the package's file as a shell variable.

dependencies

vercmp and shsort.

usage

./versions.sh <package> [timeout]

<package> is a package name corresponding to a subdirectory in pkg.

[timeout] is the number of seconds curl will spend trying to get each url listed in the package's urls list file before moving on to the next line. if all urls time out, versions fails with an error message.