github.com/benhoyt/goawk@v1.8.1/testdata/t.re4 (about)

     1  BEGIN {	r1 = "xxx"
     2  	r2 = "xxx" ":"
     3  	r3 = ":" r2
     4  	r4 = "a"
     5  }
     6  
     7  $0 ~ r1	{ print $0 " matches " r1 }
     8  $0 ~ r2	{ print $0 " matches " r2 }
     9  $0 ~ r3	{ print $0 " matches " r3 }
    10  $0 ~ r4	{ print $0 " matches " r4 }