rot13x()

function rot13x(str,    from, to, x, y, z, letter, char, buf) {
 
# rot13x for awk - Topcat Software LLC. 2010
# http://www.topcat.hypermart.net/index.html
# rot13 cipher extended to include digits
#
# more info about rot13 at: http://en.wikipedia.org/wiki/ROT13
# a modification of the example found at:
# http://www.miranda.org/~jkominek/rot13/awk/
#
# example:
#
# foo = rot13x("some string')
# bar = rot13x(foo)
# print foo
# print bar
 
    from = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
    to   = "NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm5678901234"
    x    = 62 # length from | to
    y    = length(str)
 
    for (z = 1; z <= x; z++) {
         letter[substr(from, z, 1)] = substr(to, z, 1)
    }
 
    for (z = 1; z <= y; z++) {
        char = substr(str, z, 1)
        buf  = (char in letter) ? buf letter[char] : buf char
    }
 
    return buf
 
}