Is there a better way to filter the last character?

[pexcn]

scripts/pac/whitelist.sh#L31

# replace last line `,` to empty
sed -i '$ s/,//g' ${WHITELIST_CONTENT}

# replace last character to empty
sed -i '$ s/.$//g' ${WHITELIST_CONTENT}

[pexcn]

Reference

1. https://stackoverflow.com/questions/3675169/how-to-shave-off-last-character-using-sed
2. https://stackoverflow.com/questions/3576139/sed-remove-string-only-in-the-last-line-of-the-file