I have Ubuntu 14.10. 
I've installed osmosis from apt. I downloaded mapfile-writer from here 

<http://repo.typesafe.com/typesafe/simple/sonatype-snapshots-cache/org/mapsforge/mapsforge-map-writer/0.4.0-SNAPSHOT/mapsforge-map-writer-0.4.0-20140127.161606-1.jar>

I put mapwriter to /usr/bin and /home/.openstreetmap/osmosis/plugins (just in case)

But when I run following command I get an error

```
/usr/bin/osmosis --read-xml file=UA.osm  --mapfile-writer file=dnipropetrovsk.map bbox=47.45,32.94,49.19,36.94 type=hd

```

:

```
SEVERE: Execution aborted. org.openstreetmap.osmosis.core.OsmosisRuntimeException: Task type mapfile-writer doesn't exist.
    at org.openstreetmap.osmosis.core.pipeline.common.TaskManagerFactoryRegister.getInstance(TaskManagerFactoryRegister.java:60)
    at org.openstreetmap.osmosis.core.pipeline.common.Pipeline.buildTasks(Pipeline.java:50)
    at org.openstreetmap.osmosis.core.pipeline.common.Pipeline.prepare(Pipeline.java:112)
    at org.openstreetmap.osmosis.core.Osmosis.run(Osmosis.java:86)
    at org.openstreetmap.osmosis.core.Osmosis.main(Osmosis.java:37)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchStandard(Launcher.java:328)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:238)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:408)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:351)
    at org.codehaus.classworlds.Launcher.main(Launcher.java:31)

```