This may be a couple questions in one, but this problem has me stuck. I have a text file with groupings of four lines separated by an empty line. The first line of every grouping begins with a '>' symbol. I want to delete all instances of groupings with identical first lines, except for the first instance of the grouping. First thing that comes to mind is using sed but cant think of a good way to implement. Would be grateful for any help!
>abc1234.54321 linea1 lineaa1 lineaaa1 >def56789034 linea1 lineaa1 lineaaa1 >abc1234.54321 linea2 lineaa2 lineaaa2 >def56789034 linea2 lineaa2 lineaaa2
>abc1234.54321 linea1 lineaa1 lineaaa1 >def56789034 linea1 lineaa1 lineaaa1