ud - Utility for replacing elements by id within html files.

§ Quick start

    go get -u sogvin.com/ud

Replace an element by id

    echo "<em>new thing</em>" | ud -w -i "someid" -html index.html

which is same as

    echo '<em id="someid">new thing</em>' | ud -w -html index.html

Note! when `-i` flag is not given `-c` has no effect, it will always
replace the identified element.

Replace content of element by id use the `-c` flag

    echo "<em>new thing</em>" | ud -w -c -i "someid" -html index.html


§ Primary usecase

The primary reason for this tool was to simply generate and update
image maps within html when working with graphviz documents

    dot -Tcmapx somegraph.dot | ud -w -html index.html