Question

I have to maintain a large old project project where my forerunners (for lack of version control) have turned large portions of code into comments.
Now that we have everything in version control, I feel we no longer need these comments.
The code in those comments has rotten anyway.

I would like to find the longest of those comments. It would be nice to have a way that gives me all files that have, let’s say, more than 20 consecutive comment lines.
As far as I can tell only // has been used. Finding /* */ is not necessary (probably even harmful because it’d find all the rotten javadoc… sigh).

Answer 1

Howabout this:

grep -ERn '^[[:space:]]*//' root_directory

The -E uses ‘extended’ regexes

The -R makes it recurse directories

The -n prints the filnames with line numbers

Then you can easily process this list to look for consecutive matches – just look for a block where the line number increases by one per line of output.

This assumes you don’t want to match lines like this:

int x = foo; // some comment

But only lines that are completely comments:

// this is a comment

---

Update:

Here’s a short Python script to process the output of the above grep:

import sys

filenames_of_interest = set()
filename = None
prev_line_num = 0
comment_count = 0
for line in sys.stdin.readlines():
        this_filename, line_num, _ = line.split(':',2)
        line_num = int(line_num)
        if this_filename != filename:
                comment_count = 0
                filename = this_filename
        elif line_num != prev_line_num + 1:
                comment_count = 0
        prev_line_num = line_num
        comment_count += 1
        if comment_count > 20:
                filenames_of_interest.add(filename)

print "files with blocks of comments:"
for i in filenames_of_interest:
        print ' ', i

It won’t treat files with colons in their name correctly, but shouldn’t be hard to modify to deal with that if it’s an issue.