Something

#!/bin/sh

for x in `ls /var/lib/asterisk/sounds/outboundmsgs_temp/*.wav`
do
        a=`echo $x | perl -pe 's/\w{3}$//'`
        a=${a:43:1000}
        wav="wav"
        gsm="gsm"
        sox /var/lib/asterisk/sounds/outboundmsgs_temp/"$a$wav" -r 8000 -c1 /var/lib/asterisk/sounds/outboundmsgs/"$a$gsm" resample -ql
        rm /var/lib/asterisk/sounds/outboundmsgs_temp/"$a$wav" > /dev/null 2>&1
done