ssed from the file name if this option
           is not specified and the file contents name no language yet.

    --no-obsolete
           Drop obsolete messages.

    --no-finished
           Drop finished messages.

    --sort-contexts
           Sort contexts in output TS file alphabetically.

    --locations {absolute|relative|none}
           Override how source code references are saved in TS files.
           Default is absolute.

    --no-ui-lines
           Drop line numbers from references to UI files.

    --verbose
           be a bit more verbose

Long options can be specified with only one leading dash, too.

Return value:
    0 on success
    1 on command line parse failures
    2 on read failures
    3 on write failures