regex - sed token from : delimited string -

i tried searching answer lost in questions. have shell script follows:

#!/bin/ksh  if [ $# -eq 1 ];     exit -1 fi   processinfo $1

at point, processinfo returns string of format: param1:param2:param3:param4:param5

i want capture param4 variable. ex: param4= processinfo $1 | sed regex

it seems simple sed , regex lost track of it. pls help

param4=$(processinfo $1 | awk -f: '{print $4}')

shell