Here are some crude one-liners: 
    perl -ne 'END{print"$v\t$k\n"while($k,$v)=each%h} $h{substr$_,0,5}
+++' file

    perl -ne 'END{printf"%7d %s\n",$h{$_},$_for keys%h} $h{substr$_,0,
+5}++' file

    perl -pe '$h{substr$_,0,5}++ }{ print"$h{$_}\t$_\n"for+keys%h' fil
+e

[download]

If you have GNU uniq then you can do the following:     sort file | uniq -w5 -c

However, the -w option isn't part of classical uniq.

--
John.

In reply to Re: Counting lines starting with a unique string by jmcnamara
in thread Counting lines starting with a unique string by ezekiel

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