perl -e 'my $x=q|v09.11-e020|;$x =~  m/^v[0-9][0-9]\.[0-9][0-9]-[a-z][0-9][0-9][0-9]/ and print " match\n"'
#Prints ' match'

##</code><code>##

 m/^v\d{2}\.\d{2}-[a-z]\d{3}/