feat: add job.background and bg command

job.go

@@ -112,6 +112,7 @@ func (j *job) lua() rt.Value {
 		"stop": {j.luaStop, 0, false},
 		"start": {j.luaStart, 0, false},
 		"foreground": {j.luaForeground, 0, false},
+		"background": {j.luaBackground, 0, false},
 	}
 	luaJob := rt.NewTable()
 	util.SetExports(l, luaJob, jobFuncs)
@@ -154,7 +155,14 @@ func (j *job) luaForeground(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 
 	// lua code can run in other threads and goroutines, so this exists
 	jobs.foreground = true
-	err := j.foreground()
+	// this is kinda funny
+	// background continues the process incase it got suspended
+	err := j.background()
+	if err != nil {
+		return nil, err
+	}
+
+	err = j.foreground()
 	if err != nil {
 		return nil, err
 	}
@@ -163,6 +171,19 @@ func (j *job) luaForeground(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 	return c.Next(), nil
 }
 
+func (j *job) luaBackground(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
+	if !j.running {
+		return nil, errors.New("job not running")
+	}
+
+	err := j.background()
+	if err != nil {
+		return nil, err
+	}
+
+	return c.Next(), nil
+}
+
 type jobHandler struct {
 	jobs map[int]*job
 	latestID int

job_unix.go

@@ -26,3 +26,13 @@ func (j *job) foreground() error {
 
 	return nil
 }
+
+func (j *job) background() error {
+	proc := j.handle.Process
+	if proc == nil {
+		return nil
+	}
+
+	proc.Signal(syscall.SIGCONT)
+	return nil
+}

job_windows.go

@@ -9,3 +9,7 @@ import (
 func (j *job) foreground() error {
 	return errors.New("not supported on windows")
 }
+
+func (j *job) background() error {
+	return errors.New("not supported on windows")
+}

nature/commands/bg.lua

@@ -0,0 +1,15 @@
+local commander = require 'commander'
+
+commander.register('bg', function()
+	local job = hilbish.jobs.last()
+	if not job then
+		print 'bg: no last job'
+		return 1
+	end
+
+	local err = job.background()
+	if err then
+		print('bg: ' .. err)
+		return 2
+	end
+end)