diff --git a/src/bin/lua.lua b/src/bin/lua.lua
index 0276c68..2aaafd6 100644
--- a/src/bin/lua.lua
+++ b/src/bin/lua.lua
@@ -1,6 +1,3 @@
-local ok, err = xpcall(function(...)
-local tty = ...
-io.stdin, io.stdout = tty, tty
 local term = dofile('/lib/term.lua').wrap(io) --TODO require()
 
 term:write(_VERSION, ' // ', _OSVERSION, '\n')
@@ -49,7 +46,5 @@ end
 if results.n > 1 then term:write('\n') end
 
 goto repl
-end, function(e) return debug.traceback(tostring(e)) end, ...)
-if not ok then error(err, 0) end
 
 -- vi: set ts=2:
diff --git a/src/bin/multitty.lua b/src/bin/multitty.lua
index 19bdf07..a2c64dd 100644
--- a/src/bin/multitty.lua
+++ b/src/bin/multitty.lua
@@ -144,7 +144,7 @@ local function createTerm(screen, prog, ...)
 	component.invoke(gpu, 'setResolution', w, h)
 	component.invoke(gpu, 'fill', 1, 1, w, h, ' ')
 
-	local process = assert(kitn.createProcess(prog, stdio, ...)) --TODO set io via createProcess args
+	local process = assert(kitn.createProcess({ path = prog, stdin = stdio, stdout = stdio, stderr = stdio }, ...))
 	return process, stdio
 end
 
diff --git a/src/kernel/00_preamble.lua b/src/kernel/00_preamble.lua
index 21bcfde..48c1518 100644
--- a/src/kernel/00_preamble.lua
+++ b/src/kernel/00_preamble.lua
@@ -60,7 +60,11 @@ do
 		if ok then
 			return ok
 		else
-			error(format('bad argument #%d (%s expected, got %s)', i, concat({...}, ' or '), t), 3)
+			if type(i) == 'number' then
+				error(format('bad argument #%d (%s expected, got %s)', i, concat({...}, ' or '), t), 3)
+			else
+				error(format('bad argument %s (%s expected, got %s)', i, concat({...}, ' or '), t), 3)
+			end
 		end
 	end
 end
diff --git a/src/kernel/04_environment.lua b/src/kernel/04_environment.lua
index 279d85f..0e0d423 100644
--- a/src/kernel/04_environment.lua
+++ b/src/kernel/04_environment.lua
@@ -9,7 +9,7 @@ given <https://ocdoc.cil.li/tutorial:custom_oses#what_s_available>:
 ]]
 
 
-envBase._OSVERSION = 'kitn 0.2.1-beta.5' --prefer [openloader, openos] "$name $ver" over plan9k "$name/$ver"
+envBase._OSVERSION = 'kitn 0.2.1-beta.6' --prefer [openloader, openos] "$name $ver" over plan9k "$name/$ver"
 envBase.kitn = {}
 envBase._G, envBase.load = nil
 
@@ -159,10 +159,33 @@ function fillEnv(proc, uenv)
 		return co
 	end
 
-	function ukitn.createProcess(path, ...)
-		checkArg(1, path, 'string')
+	local function assertFile(label, file)
+		if isFile(file) then
+			return file
+		else
+			error(label .. ' is not a file', 3)
+		end
+	end
+
+	function ukitn.createProcess(init, ...)
+		local initT = checkArgEx(1, init, 'string', 'table')
+		local path, stdin, stdout, stderr
+
+		if initT == 'string' then
+			path = init
+		else
+			path, stdin, stdout, stderr = init.path, init.stdin, init.stdout, init.stderr
+		end
+
+		stdin = stdin and assertFile('stdin', stdin) or assertFile('inherited stdin', uio.stdin)
+		stdout = stdout and assertFile('stdout', stdout) or assertFile('inherited stdout', uio.stdout)
+		stderr = stderr and assertFile('stderr', stderr) or assertFile('inherited stderr', uio.stderr)
+
 		local co, info = createProcess(path, proc)
 		if not co then return nil, info end
+
+		local newio = info.env.io
+		newio.stdin, newio.stdout, newio.stderr = stdin, stdout, stderr
 		runqueue[co] = pack(...)
 		return co
 	end
diff --git a/src/lib/term.lua b/src/lib/term.lua
index d435394..d5e114a 100644
--- a/src/lib/term.lua
+++ b/src/lib/term.lua
@@ -61,8 +61,15 @@ end
 --write strings to stderr with optional styling.
 --see `mt:write` for how styling is interpreted.
 function mt:error(...)
-	--TODO use wrapped stderr
-	return self:write({ fg = 0xff0000, ... })
+	local args = table.pack(...)
+	args.fg = 0xff0000
+	local caps = self.stderr.tty
+	if caps then
+		writeStyled(caps, self.stderr, args)
+	else
+		writeUnstyled(self.stderr, args)
+	end
+	return self
 end
 
 --prompt the user for a line of input.