[SOLVED] How to grep for pointers to pointers (in C++ source)?

Issue

I have been using grep to perform recursive search of text inside a directory, i.e.

grep -Hrn "some-text" ./

However, I am running into some troubles when I need to search for pointers or pointers of pointers:

grep -Hrn "double**" ./
> grep: repetition-operator operand invalid

I have made some attempts to go around this, including some I found via Google searches:

grep -Hrn "double[**]" ./
grep -Hrn "double[*][*]" ./

but neither seems to work. Any pointers?

Solution

You have to escape * by using \. For example

$ echo "double***" | grep "double\*\*\*"
double***

If you don't escape * it matches the character before the * zero or more times. One * would therefore match e.g. doubleeeee but the second * results in an error since the operand (the character before the *) is not valid since it's again *. That's exactly what the error message tells you.

The version using [] should also work. As mentioned in the comments the issue might be that your variable declarations contain whitespace. The following regex matches these (now using the * operator):

$ echo "double  **" | grep "double\s*\*\*"
double  **

Answered By - dtell