Get the PID of a process launched in the same command line

Question

I want to launch in bash a hello.sh script that does many things (writing in a file, printing in the screen), but I want to get its PID dumping it in a file, but I want to do it in the same command line because I could have different processes with the same file (many hello.sh launched).

So, I would like something like (pseudo-code): sh hello.sh > get_pid > pid_to_log. Thx.

Answer 1

You can do this

./myscript.sh & echo $! >> log.pid

Then you will store your PID in a file. But perhaps you need to store also the date and hour.

./sleep.sh & echo $! `date` >> log.pid

Example

$ more sleep.sh
sleep 10
$ ./sleep.sh & echo $! `date` >> log.pid
[1] 9588
$ ./sleep.sh & echo $! `date` >> log.pid
[2] 9640
$ ./sleep.sh & echo $! `date` >> log.pid
[3] 9646
$ cat log.pid
9588 Wed Jul 8 14:03:19 CEST 2020
9640 Wed Jul 8 14:03:22 CEST 2020
9646 Wed Jul 8 14:03:23 CEST 2020