Re: Checking if the other end of a fifo is open

[Dave Smith]

Nicholas Leippe wrote:
kill -USR1 # should do it
$$ # has the pid of the current process--just pass that in to the child
  

Okay, got it. This sandbox script simulates a blocking call (sleeping 
for 2 seconds in this case) in a backgrounded subshell, which signals 
when it's done. Thanks Nicholas!

#!/bin/bash

trap "flag=1" SIGUSR1

flag=0
(sleep 2 ; kill -SIGUSR1 $$) &

# Wait for the flag to get raised, or give up after a while:
count=0
while true; do
    if [ $flag -eq 1 ]; then
        echo Yay, it worked.
        break
    else
        echo Still waiting
        let count=$count+1

        if [ $count -gt 100 ]; then
            echo Giving up
            exit 1
        fi
    fi
    sleep 0.1
done


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