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.

---

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

Answer 2

What you say you want to do is not what you're telling sed to do.

You want to insert a number into a tag or replace it if present. What you're trying to tell sed to do is to replace a span tag and its contents, if any or a number, with the value of in a shell variable.

You're also employing a lot of complex, annoying and erorr-prone escape sequences which are just not necessary.

Here's what you want:

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

Note the differences:

• Added -r to turn on extended expressions without which your capture pattern would not work.
• Used | instead of / as the delimiter for the substitution so that escaping / would not be necessary.
• Single-quoted the sed expression so that escaping things inside it from the shell would not be necessary.
• Included the matched span tag in the replacement section so that it would not get deleted.
• In order to expand the unlockedCount variable, closed the single-quoted expression, then later re-opened it.
• Omitted cat | which was useless here.

I also used double quotes around the shell variable expansion, because this is good practice but if it contains no spaces this is not really necessary.

It was not, strictly speaking, necessary for me to add -r. Plain old sed will work if you say \([0-9]\{0,\}\), but the idea here was to simplify.