transcript

gistfile1.txt

$ cat run
cat run
#!/bin/sh

nohup bash -c 'while true; do sleep 10; done' </dev/null &> sleeper.log &
echo $! > /tmp/sleeper.pid
;
$ sudo ./run
sudo ./run
[sudo] password for pak:

$ cat /tmp/sleeper.pid
cat /tmp/sleeper.pid
27167

$ ps auxwww | grep 27167
ps auxwww | grep 27167
root     27167  0.0  0.0  63828  1052 pts/5    S    08:36   0:00 bash -c while true; do sleep 10; done
pak      27237  0.0  0.0  61148   728 pts/5    S+   08:36   0:00 grep 27167

$ kill -0 27167
kill -0 27167
bash: kill: (27167) - Operation not permitted

$ echo $!
echo $!
31020

$ kill -0 27167
kill -0 27167
bash: kill: (27167) - Operation not permitted

$ echo $?
echo $?
1

$ perl58 -e 'print kill(0, 27167)'
perl58 -e 'print kill(0, 27167)'
0
$