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+# efa-m - Commandline Public Transit Departure Monitor
+
+efa-m is a commandline client and Perl module for EFA public transit departure
+interfaces such as [efa.vrr.de](https://efa.vrr.de/vrr/XSLT_DM_REQUEST). See
+the [Travel::Status::DE::VRR
+homepage](https://finalrewind.org/projects/Travel-Status-DE-VRR/) for details.
+
+## Installation
+
+efa-m is available as
+[perl-travel-status-de-vrr-git](https://aur.archlinux.org/packages/perl-travel-status-de-vrr-git/)
+in the archlinux User Repository (AUR).
+
+For other distributions, you have four installation options:
+
+* Nightly `.deb` builds for Debian-based distributions
+* Installing the latest release from CPAN
+* Installation from source
+* Using a Docker image
+
+Except for Docker, __efa-m__ is available in your PATH after installation. You
+can run `efa-m --version` to verify this. Documentation is available via
+`man efa-m`.
+
+### Nightly Builds for Debian
+
+[lib.finalrewind.org/deb](https://lib.finalrewind.org/deb) provides Debian
+packages of both development and release versions. Note that these are not part
+of the official Debian repository and are thus not covered by its quality
+assurance process.
+
+To install the latest release, run:
+
+```
+wget https://lib.finalrewind.org/deb/libtravel-status-de-vrr-perl_latest_all.deb
+sudo dpkg -i libtravel-statusg-de-vrr-perl_latest_all.deb
+sudo apt --fix-broken install
+rm libtravel-status-de-vrr-perl_latest_all.deb
+```
+
+For a (possibly broken) development snapshot of the Git master branch, run:
+
+```
+wget https://lib.finalrewind.org/deb/libtravel-status-de-vrr-perl_dev_all.deb
+sudo dpkg -i libtravel-status-de-vrr-perl_dev_all.deb
+sudo apt --fix-broken install
+rm libtravel-status-de-vrr-perl_dev_all.deb
+```
+
+Note that dpkg, unlike apt, does not automatically install missing
+dependencies. If a dependency is not satisfied yet, `dpkg -i` will complain
+about unmet dependencies and bail out. `apt --fix-broken install` installs
+these dependencies and also silently finishes the Travel::Status::DE::VRR
+installation.
+
+Uninstallation works as usual:
+
+```
+sudo apt remove libtravel-status-de-vrr-perl
+```
+
+### Installation from CPAN
+
+Travel::Status::DE::VRR releases are published on the Comprehensive Perl
+Archive Network (CPAN) and can be installed using standard Perl module tools
+such as `cpanminus`.
+
+Before proceeding, ensure that you have standard build tools (i.e. make,
+pkg-config and a C compiler) installed. You will also need the following
+libraries with development headers:
+
+* libssl
+* libxml2
+* zlib
+
+Now, use a tool of your choice to install the module. Minimum working example:
+
+```
+cpanm Travel::Status::DE::VRR
+```
+
+If you run this as root, it will install script and module to `/usr/local` by
+default.
+
+### Installation from Source
+
+In this variant, you must ensure availability of dependencies by yourself.
+You may use carton or cpanminus with the provided `Build.PL`, Module::Build's
+installdeps command, or rely on the Perl modules packaged by your distribution.
+On Debian 10+, all dependencies are available from the package repository.
+
+To check whether dependencies are satisfied, run:
+
+```
+perl Build.PL
+```
+
+If it complains about "... is not installed" or "ERRORS/WARNINGS FOUND IN
+PREREQUISITES", it is missing dependencies.
+
+Once all dependencies are satisfied, use Module::Build to build, test and
+install the module. Testing is optional -- you may skip the "Build test"
+step if you like.
+
+If you downloaded a release tarball, proceed as follows:
+
+```
+./Build
+./Build test
+sudo ./Build install
+```
+
+If you are using the Git repository, use the following commands:
+
+```
+./Build
+./Build manifest
+./Build test
+sudo ./Build install
+```
+
+### Running efa-m via Docker
+
+An efa-m image is available on Docker Hub. It is intended for testing purposes:
+due to the latencies involved in spawning a container for each efa-m
+invocation, it is less convenient for day-to-day usage.
+
+Installation:
+
+```
+docker pull derfnull/efa-m:latest
+```
+
+Use it by prefixing efa-m commands with `docker run --rm
+derfnull/efa-m:latest`, like so:
+
+```
+docker run --rm derfnull/efa-m:latest --version
+```
+
+Documentation is not available in this image. Please refer to the
+[online efa-m manual](https://man.finalrewind.org/1/efa-m/) instead.