Implementing infinite wait in shell scripting

If you have GNU coreutils, which accepts floating-point seconds, you can try:

sleep inf

This should block until the 64-bit timestamp wraparound.

Here's a solution without a loop:

#!/usr/local/bin/dash

echo $$

# -$$: kill process group (parent and children)
#trap 'trap - TERM; kill 0' TERM
#trap 'trap - INT TERM; kill 0' INT TERM

trap 'trap - TERM; kill -s TERM -- -$$' TERM

tail -f /dev/null & wait

exit 0

you can use a named pipe for your read:

mkfifo /tmp/mypipe
#or mknode /tmp/mypipe p

if you later want to send different arbitrary "signals" to the pipe, the read can be use in combination with a case statement to take appropriate actions (even useful ones)

while read SIGNAL; do
    case "$SIGNAL" in
        *EXIT*)break;;
        *)echo "signal  $SIGNAL  is unsupported" >/dev/stderr;;
    esac
done < /tmp/mypipe