Note that your reformatting isn't necessary equivalent; in the reformatted example, you have introduced whitespace, which may be significant it can certainly be significant in HTML. Compare: 
    Hello, <b>w</b>orld

[download]
with 
    Hello,
      <b>
         w
      </b>
    orld

[download]
The former will typically be rendered by a browser as two words; the latter as three.

A very simplistic beautifier is: s!(/?>)!\n$1!g. It doesn't do indentation, but it does fold long lines, and, because it inserts the newline inside a tag it doesn't introduce whitespace in the data. Of course, if you have > symbols in PCDATA content (SCRIPT and STYLE elements, and attribute values), this may break things.

In reply to Re: Beautifying some SGML? by JavaFan
in thread Beautifying some SGML? by markww

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


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