##
perl -le 'print $x = "abcdefgxxabcdefgzzabcdsjfhkdfab"; print $2 if $x =~ /((\w{2,}).*?\2.*?)+/;'
abcdefgxxabcdefgzzabcdsjfhkdfab
abcdefg
##
##
perl -le 'print $x = "abcdefgxxabcdefgzzabcdsjfhkdfab"; print $2 if $x =~ /((\w{2,}?).*?\2.*?)+/;'
abcdefgxxabcdefgzzabcdsjfhkdfab
cd