Why doesn't SIGINT work on a background process in a script?

I have the following in a script: yes >/dev/null & pid=$! echo $pid sleep 2 kill -INT $pid sleep 2 ps aux | grep yes When I run it, the output shows that yes is still running by the end of the script. However, if I run the commands interactively then the process terminates successfully, as in the following: > yes >/dev/null & 9967 > kill -INT 9967 > ps aux | grep yes sean ... 0:00 grep yes Why does SIGINT terminate the process in the interactive instance but not in the scripted instance? EDIT Here's some supplementary information that may help to diagnose the issue. I wrote the following Go program to simulate the above script. package main import ( "fmt" "os" "os/exec" "time" ) func main() { yes := exec.Command("yes") if err := yes.Start(); err != nil { die("%v", err) } time.Sleep(time.Second*2) kill := exec.Command("kill", "-INT", fmt.Sprintf("%d", yes.Process.Pid)) if err := kill.Run(); err != nil { die("%v", err) } time.Sleep(time.Second*2) out, err := exec.Command("bash", "-c", "ps aux | grep yes").CombinedOutput() if err != nil { die("%v", err) } fmt.Println(string(out)) } func die(msg string, args ...interface{}) { fmt.Fprintf(os.Stderr, msg+"\n", args...) os.Exit(1) } I built it as main and running ./main in a script, and running ./main and ./main & interactively give the same, following, output: sean ... 0:01 [yes] sean ... 0:00 bash -c ps aux | grep yes sean ... 0:00 grep yes However, running ./main & in a script gives the following: sean ... 0:03 yes sean ... 0:00 bash -c ps aux | grep yes sean ... 0:00 grep yes This makes me believe that the difference has less to do on Bash's own job control, though I'm running all of this in a Bash shell.