regex - Replacing HTML tag content using sed

Question

I'm trying to replace the content of some HTML tags in an HTML page using sed in a bash script. For some reason I'm not getting the proper result as it's not replacing anything. It has to be something very simple/stupid im overlooking, anyone care to help me out?

HTML to search/replace in:

Unlocked <span id="unlockedCount"></span>/<span id="totalCount"></span> achievements for <span id="totalPoints"></span> points.

sed command used:

cat index.html | sed -i -e "s/<span id="unlockedCount">([0-9]{0,})</span>/${unlockedCount}/g" index.html 

The point of this is to parse the HTML page and update the figures according to some external data. For a first run, the contents of the tags will be empty, after that they will be filled.

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EDIT:

I ended up using a combination of the answers which resulted in the following code:

sed -i -e 's|<span id="unlockedCount">([0-9]{0,})</span>|<span id="unlockedCount">'"${unlockedCount}"'</span>|g' index.html

Many thanks to @Sorpigal, @tripleee, @classic for the help!

Answer 1

Try this:

sed -i -e "s/(<span id="unlockedCount">)(</span>)/1${unlockedCount}2/g" index.html