Question

I am processing one binary file in which I want to retrieve first 4 bytes, next 4 bytes, again 4 bytes and then rest of the file contents except last 8 bytes of last line.

I have tried with this line file.read.scan(/(.{4})(.{4})(.{4})(.*\w)(.{8})/).each do |a,b,c,d,e| but after some iterations this regex starts from some line in between with first 4 bytes, next 4 bytes, next 4 bytes pattern. Because of this my condition check fails.

I want to do following.
Read first 4 bytes of first line of file, then bytes 5 to 7, then bytes 8 to 11, then rest of the file content except last 8 bytes of last line of the file.

What could be the regex for this in Ruby?

Answer 1

How about:

/(.{4})(.{3})(.{4})(.*).{8}/m