Match Awk entire record using regular expression

Using Awk, I want to match the entire entry using regex. By default, regex matching refers to portions of the record.

Ideal solution:

• Shared across all fields, regardless of the field separator used.
• Don't treat all input as one field and parse it manually using string functions.
• Work mostly and don't be specific to gawk for example.

However, any and all solutions are of interest as long as they use Awk without calling external programs .

For example, I have:

$ ls
indata.txt  t1.awk
$ cat indata.txt 
a1010_
1010_
1010_b
$ cat t1.awk 
/[01]*_[01]*/ { print $0 }

      

        
        
        
      

    

I get:

$ awk -f t1.awk indata.txt
a1010_
1010_
1010_b

      

        
        
        
      

    

This is the result I'm looking for:

$ awk -f t1.awk indata.txt
1010_