I need a little help here 9000,

I was writing the first code on installing the script, everything was going well until writing the line

iwconfig wlan0 mode ad-hoc

it returns the following,

+ iwconfig wlan0 mode ad-hoc
/bin/sh: iwconfig: not found

Is this good? is it part of the process? I'm going to keep writing the code but if there is something wrong please reply, and thanks for your help