Just a start: 
perl -wne '
  $h{$1}++ if /bn(\d{4}),/ }{$,="\t"; print %h, "\n"
' datafile

[download]
To see the actual code, use:
perl -MO=Deparse -wne '
  $h{$1}++ if /bn(\d{4}),/ }{$,="\t"; print %h, "\n"
'

[download]

-- 
Ruud

In reply to Re: Parsing a Flat File and counting occurances of numbers? by druud
in thread Parsing a Flat File and counting occurances of numbers? by batcater98

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