urldecode with AWK
awk -niord '{printf RT?$0chr("0x"substr(RT,2)):$0}' RS=%..
Fast and simple awk urldecoder!
Note: Parameter -n is specific to GNU awk
Sample Output
echo -e "asdf%2Fxx%2Cx\n%2F%2Cxx" | awk -niord '{printf RT?$0chr("0x"substr(RT,2)):$0}' RS=%..
asdf/xx,x
/,xx
www.bb.com