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I am running a cron on every two minutes. From the cron I am running other shell scripts in background with "&". After cron exits spawned shell script process still runs, this is desired behavior.

But does it lead to any zombi process when child script exits. Do I need to consider any special cases?

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up vote 2 down vote accepted

it probably will (I should check to be sure) but in any case you can store the PIDs of the forked processes and kill them on exit:

my_forked_process & my_forked_pid=$!

since you said "other shells" I would assume there's a few so we should use an array:

my_forked_process1 & my_forked_pids+=($!)
my_forked_process2 & my_forked_pids+=($!)

then you kill them like this on exit:

for pid in "${my_forked_pids[@]}"; do
    kill "$pid"

[bonus] if you wrap the previous on a function you can set a trap to run it when the script exits regardless of the moment (safety for when it's killed prematurely):

trap cleanup_function 0

0 is a special signal that means "on exit"

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