echo '手机' | tr -d '\n' | xxd -plain | sed 's/\(..\)/%\1/g'  

echo '手机' |tr -d '\n' |od -An -tx1|tr ' ' %

url="要解码的URL地址"
printf $(echo -n $url | sed 's/\\/\\\\/g;s/\(%\)\([0-9a-fA-F][0-9a-fA-F]\)/\\x\2/g')"\n"