need help with build prop

can you pls tell me why this code is not working in recovery

sed -i 's/HTC_Sense5_Boot.mp3/HTC_Sense5_Boot.mp3.bak/g' /system/customize/resource;

and this also not working

mv HTC_Sense5_Boot.mp3 HTC_Sense5_Boot.mp3.bak

file is located in /system/customize/resource in htc m8
recovery twrp 2.8.7.0.