need help with shell coding

need help with some shell coding
somebody pls help me why this code is not working in recovery

(1)
aim- to rename m8,s boot sound from mp3 to mp3.bak
sed -i 's/HTC_Sense5_Boot.mp3/HTC_Sense5_Boot.mp3.bak/g' /system/customize/resource;
or
mv HTC_Sense5_Boot.mp3 HTC_Sense5_Boot.mp3.bak /system/customize/resource;
file is located in /system/customize/resource in htc m8

(2)
aim-add a new line media _rw to get sd card write access
sed -e '/WRITE_EXTERNAL_STORAGE" >$/N;s/\n\(\([ \t]*\)<group gid="sdcard_rw".*$\)/\n<group gid="media_rw" \/>\n/' -i /system/etc/permissions/platform.xml
file is located in /system/etc/permissions/platform.xml in htc m8

(3)
and this also not working
aim-rename a string in build prop
sed -i 's/ro.product.device=htc_m8/ro.product.device=htc_One/g' /system/build.prop;
sed -i 's/ro.build.product=htc_m8/ro.build.product=htc_One/g' /system/build.prop;
file is located in /system/build.prop in htc m8

(4)
is there any editor to find coding mistakes in .sh programs which we run in update zip

(5)
how to rename a system file call ime.apk to ime.apk.bak by a shell and by edify want to know both ways
file is located in /system/app/ime/ime.apk in htc m8

device-htc one m8 international
os-lollipop
skin-sense 6
kernel and rom-stock dev edition 4.16.1540.8
bootloader-unlocked
security status-S-off
recovery i use-twrp 2.8.7.0.
i already post it in question answer thread but no luck:crying: