Convert a MAC Address with Hyphen to Colons

If you have a MAC delimited with hyphens:

xx-xx-xx-xx-xx-xx
You can convert it to use colons using sed:
echo xx-xx-xx-xx-xx-xx | sed ’s/-/:/g’
Which will output as:
xx:xx:xx:xx:xx:xx
Anything can be replaced:
echo xx-xx-xx-xx-xx-xx | sed ’s/-/%/g’
Would output:
xx%xx%xx%xx%xx%xx