awk on unix AS/400 (Qshell)

In linux, I can do this echo "hello" > a.txt awk 'sub("l", "x" )' a.txt hexlo But if I do it on Qshell, I get: echo "hello" > a.txt awk 'sub("l", "x" )' a.txt awk: 0602-562 Field $($ I have no idea of what's going on, cannot find much about awk on qshell online. Please help...