How to grep on source code without catching comments

grep works on pure text and does not know anything about the underlying syntax of your C program. Therefore, in order not search inside comments you have several options:

1. Strip C-comments before the search, you can do this using gcc -fpreprocessed -dD -E yourfile.c For details, please see https://stackoverflow.com/questions/2394017/remove-comments-from-c-c-code

2. Write/use some hacky half-working scripts like you have already found (e.g. they work by skipping lines starting with // or /*) in order to handle the details of all possible C/C++ comments (again, see the previous link for some scary testcases). Then you still may have false positives, but you do not have to preprocess anything.

3. Use more advanced tools for doing "semantic search" in the code. I have found "coccigrep": http://home.regit.org/software/coccigrep/ This kind of tools allows search for some specific language statements (i.e. an update of a structure with given name) and certainly they drop the comments.

You can try a naive approach to match non-comments like this:

 $ egrep -v "^(//|/\*| \*)" sourcecode

This will only inverse match against prefixed comments - that is lines starting with either //, /*, * or */ - and hence it'll not leave out blocks that are commented out with the /* and */ pair.