Interacting with two BASH shells

Shell Programming and Scripting
1

Hi. I'm working with two BASH shells in order to perform two tasks. For simplicity, suppose that at Shell #1 I'm executing this program:

sleep 100

whose PID is 263. Meanwhile Shell #2 is waiting for its termination to follow with a second one.

I tried with:

wait 263
# Script for second task...

at Shell #2, but it throws me this message:

-bash: wait: pid 263 is not a child of this shell

Any idea of how to perform this operation?

Many thanks in advance.

2

Wouldn't it be easier to run your (first) script in the background and keep an eye on the - foregrounded - process table of the (only) shell ...

[house@leonov] sh test.bash &
[house@leonov] ps aux | grep 'sh' | grep 'test'
house   27118   11400   1588   pts/3   sh test.bash
3

Thanks for the reply. In this case I have to work on two shells, since I'm running OpenSees and Matlab at the same time.

What I need is to emulate the "wait" command in order to perform my request.

Thanks in advance.

4

Hi.

You could try something like this:

myWait
======
while [ "$(ps -ef | awk '$2 == '${1:-X})" ]; do sleep 3; done

Pass in the process ID to wait for (i.e. "myWait 5657" or "./myWait 5657")

5

Many thanks for the reply. Yes, my first try was:

while [ "$(ps c | grep 263)" ]; do sleep 1; done

But I would like to see a better solution, like the wait command. :slight_smile:

Thank you!