in reply to Re: How to know if two files (.c,.h,.cpp) are different content-wise ignoring the comments?
in thread How to know if two files (.c,.h,.cpp) are different content-wise ignoring the comments?

how can a tool diff and figure out if they are different or not after stripping the comments?

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Re^3: How to know if two files (.c,.h,.cpp) are different content-wise ignoring the comments?
by Anonymous Monk on Feb 13, 2011 at 07:01 UTC

      I am trying to use diff tool but use the -I option to ignore lines that start with "File Name:".i am using the below regular expression,there is no syntax error but the diff tool still shows changes with line that starts with "File Name:".Any idea what is going wrong?

      diff -I '[^\s*File\sName:]' file1 file2

        iphone:

        If there are differences in comments, then it's likely that there will be differences in the whitespace as well, so tell diff to ignore blank lines and other forms of whitespace. I don't know what you're running on, but on my box here, I use the options:

        • -E to ignore tab expansion
        • -b to ignore changes in whitespace
        • -w to ignore all whitespace
        • -B to ignore blank lines

        Note: I've never experimented to see if I can get by with a subset of those flags, but I suspect I can. But it's easy, so I've never found it worth the time to find out.

        ...roboticus

        When your only tool is a hammer, all problems look like your thumb.

        Where does Perl come into play here?