来自： https://snipt.net/raw/fa8984e6615a15cb903575c8460edab3/?nice

#! /bin/sh
export LANG=C


urlencode()
{
arg="$1"
i="0"
while [ "$i" -lt ${#arg} ]; do
c=${arg:$i:1}
if echo "$c" | grep -q '[a-zA-Z/:_\.\-]'; then
echo -n "$c"
else
echo -n "%"
printf "%X" "'$c'"
fi
i=$((i+1))
done
}

urldecode()
{
arg="$1"
i="0"

while [ "$i" -lt ${#arg} ]; do
c0=${arg:$i:1}
if [ "x$c0" = "x%" ]; then
c1=${arg:$((i+1)):1}
c2=${arg:$((i+2)):1}
printf "\x$c1$c2"
i=$((i+3))
else
echo -n "$c0"
i=$((i+1))
fi
done
}

urldecode "%E9%BB%84%E7%9F%B3%E5%9B%BD%E5%AE%B6%E5%85%AC%E5%9B%AD"