f(),
P = application:get_env(rebar, providers, []),
S = lists:foldl(fun(P, S) -> {ok, S2} = P:init(S), S2 end, rebar_state:new(), P),
PS = rebar_state:providers(S),
DP = lists:keysort(2,providers:get_providers_by_namespace(default, PS)),
f(Str),
Str = [begin
    Name = element(2,Pn),
    Desc = element(8,Pn),
    Opts = element(10,Pn),
    OptShort = [case {Short,Long} of
                    {undefined,undefined} -> "";
                    {undefined,_} -> ["[\\fI--",Long,"\\fR] "];
                    {_,undefined} -> ["[\\fI-",Short,"\\fR] "];
                    {_,_} ->         ["[\\fI-",Short,"\\fR|\\fI--",Long,"\\fR] "]
                end || {_,Short,Long,_,_Desc} <- Opts],
    OptLong = [case {Short,Long} of
                   {undefined,undefined} -> "";
                   {_,undefined} -> [".IP\n\\fI-",Short,"\\fR: ", Desc, "\n"];
                   {_,_} ->         [".IP\n\\fI--",Long,"\\fR: ", Desc, "\n"]
               end || {_,Short,Long,_,Desc} <- Opts],
    [".TP\n",
     "\\fB", atom_to_list(element(2,Pn)), "\\fR ", OptShort, "\n",
     Desc, "\n", OptLong] end || Pn <- DP, element(5,Pn) == true],
file:write_file("commands.out", Str).