I want a $(thing/command/variable) like PROMPT_COMMAND, but for a nonintervention shell script that runs a command every line $(in the same Bash instance). For example,
Normal
echo hel
echo hel
echo hel
echo hel
After thing
thingcom "sleep 1" # Note this would act as if this was the case
echo hel
sleep 1
echo hel
sleep 1
echo hel
sleep 1
echo hel
sleep 1