--:Minify:--
local args = {...}
local i = 1
local opt = {}

while i <= #args do
    local a = args[i]
    if a == "-l" then i=i+1; opt.newname = args[i]
    elseif a == "-p" then i=i+1; opt.password = args[i]
    elseif a == "-g" then i=i+1; opt.gid = tonumber(args[i])
    elseif a == "-d" then i=i+1; opt.homedir = args[i]
    elseif a == "-s" then i=i+1; opt.shell = args[i]
    elseif a == "-L" then opt.lock = true
    elseif a == "-U" then opt.unlock = true
    elseif a:sub(1,1) ~= "-" then opt.username = a
    else print("usermod: unknown option: " .. a); syscall.exit(1); return end
    i = i + 1
end

if not opt.username then
    print("Usage: usermod [-l newname] [-p password] [-g gid] [-d homedir] [-s shell] [-L] [-U] <username>")
    syscall.exit(1); return
end

if opt.lock and opt.unlock then
    print("usermod: -L and -U are mutually exclusive")
    syscall.exit(1); return
end

local uid = syscall.auth_getuid(opt.username)
if not uid then
    print("usermod: user '" .. opt.username .. "' does not exist")
    syscall.exit(1); return
end

local function apply(fn, ...)
    local ok, err = fn(...)
    if not ok then print("usermod: " .. tostring(err)); syscall.exit(1) end
end

if opt.newname  then apply(syscall.auth_setusername, uid, opt.newname) end
if opt.password then apply(syscall.auth_setpassword, uid, opt.password) end
if opt.gid      then apply(syscall.auth_setgid,      uid, opt.gid) end
if opt.homedir  then apply(syscall.auth_sethomedir,  uid, opt.homedir) end
if opt.shell    then apply(syscall.auth_setshell,     uid, opt.shell) end
if opt.lock     then apply(syscall.auth_lockuser,     uid) end
if opt.unlock   then apply(syscall.auth_unlockuser,   uid) end

print("usermod: updated user '" .. opt.username .. "'")