sed: how to replace a specific string

Question

I have an issue I am trying to solve with sed. My goal is to quote a the content after content= if the content is not already quoted.

Here is the concrete example:

<meta name="ProgId" content=Word.Document>
<meta name="Generator" content="Microsoft Word 15">

I would like to add quotes around Word.Document so at the end have:

<meta name="ProgId" content="Word.Document">
<meta name="Generator" content="Microsoft Word 15">

I was trying with

sed -i 's@content="\(.*\)"@content="\1"/@g' "$1"

However this is not working.

Thank you.

Answer 1

There is no " in the input behind content=, so you shouldn't match it. You could match up until a space or >.

sed 's@content=\([^"][^ >]*\)@content="\1"@'

Note that you should use XML aware tools to parse XML documents.

Answer 2

This should work:

sed -E 's/content=([^">]+)/content="\1"/'

Explanation:

In this way, you tell sed to substitute everything is after content= and before > only if it doesn't start with ". I used regex grouping to replace the content with itself surrounded by ".

Input:

<meta name="ProgId" content=Word.Document>
<meta name="Generator" content="Microsoft Word 15">

Output:

<meta name="ProgId" content="Word.Document">
<meta name="Generator" content="Microsoft Word 15">