I can't see any relationship between your code snippet and the error msg that you get. Anyhow, might be it doesn't like an empty "$q2" - so, trywhile read q1 q2 q3
do [ "$q3" ] && P="-D ps -q $q2"...
If the second value can be empty in your input file, use Corona688's proposal and adapt:while read q1 q2 q3
do [ "$q3" ] || { q3=$q2; q2=""; }
/usr/lib/lpd/pio/etc/piomkjetd mkpq_jetdirect...