Regex Question - Searching for this or that?

I want to search a file for either a character at the beginning of the line, or a blank or empty line. So for example, let's assume the end of line char is LF = chr(10)

In the text below, I want the count of the results to equal (5). Al开发者_C百科l lines beginning with the string "T" and empty but for spaces or blank lines.

=====FILE======  
This is good (count this one 1.)  
    --- one or more spaces (count this one 2.)  
Not so good  
This is also good (count this one 3.)
- intentionally blank -  (count next two 4.)
- intentionally blank -  (.5)
Can't be good  
=====END FILE===  

/^(T|\s*$)/

To match the above:

^(T.*| *)$

This will do the job:

/^([T ].+|$)/

here is a sample Perl script:

#!/usr/bin/perl
use strict;
use warnings;
use 5.12.0;

my $count;
while(<DATA>) {
    $count++ if /^([T ].+|$)/;
}
say $count;

__DATA__
This is good (count this one 1.)  

Not so good  
This is also good (count this one 3.)


Can't be good  

output: 5