note jdporter I'm surprised no one has suggested the [id://145659|GRT] yet. This is an ideal case for it. <code> my @a = <DATA>; chomp @a; @a = map { substr $_, 10 } sort map { sprintf "%10s%s", /(\d+\w{3}\d{4})/, $_ } @a; print join "\n", @a, ''; __DATA__ fwlog.14Mar2005.gz fwlog.15Mar2005.gz fwlog.16Mar2005.gz fwlog.17Mar2005.gz fwlog.18Mar2005.gz fwlog.19Mar2005.gz fwlog.1Mar2005.gz fwlog.20Mar2005.gz fwlog.21Mar2005.gz fwlog.2Mar2005.gz fwlog.3Mar2005.gz fwlog.4Mar2005.gz fwlog.5Mar2005.gz fwlog.6Mar2005.gz fwlog.7Mar2005.gz fwlog.8Mar2005.gz fwlog.9Mar2005.gz </code> 441568 441568