busybox/shell/ash_test/ash-signals/usage.tests

# no output -- default state
echo ___
trap

# assign some traps
echo ___
trap "a" EXIT INT USR1 USR2

# show them all
echo ___
trap

# show them by command substitution
echo ___
echo $(trap)

# show them by pipe
echo ___
trap | cat

# show them by process substitution
echo ___
cat <(trap)

# clear one
echo ___
trap 0 INT
echo ___
trap

# clear another
echo ___
trap "-" USR1
echo ___
trap