Below is the file 'contrib/command/init.lua' from this revision. You can also download the file.

--
--  init.lua -- Monotone Lua extension command "mtn init"
--  Copyright (C) 2008 Ralf S. Engelschall <rse@engelschall.com>
--
--  This program is made available under the GNU GPL version 2.0 or
--  greater. See the accompanying file COPYING for details.
--
--  This program is distributed WITHOUT ANY WARRANTY; without even the
--  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
--  PURPOSE.
--

register_command(
    "init", "BRANCH",
    "Place current directory under local version control.",
    "Creates a new _MTN/mtn.db database and places the local " ..
    "directory tree under version control using this database.",
    "command_init"
)

function command_init(branch)
    --  sanity check command line
    if branch == nil then
        io.stderr:write("mtn: init: ERROR: no branch specified\n")
        return
    end

    --  create new database
    execute("mtn", "--db=mtn.db", "db", "init")

    --  place current directory under version control
    execute("mtn", "--db=mtn.db", "setup", "-b", branch)

    --  place database into book-keeping directory
    execute("mv", "mtn.db", "_MTN/mtn.db")
    local txt = read_contents_of_file("_MTN/options")
    txt = string.gsub(txt, "database \"[^\"]*\"", "database \".mtn/mtn.db\"")
    options = io.open("_MTN/options", "w")
    options:write(txt)
    io.close(options)

    --  perform a simple operation so that Monotone
    --  updates the book-keeping directory
    execute("sh", "-c", "mtn stat >/dev/null 2>&1")
end