johngg@shiraz:~/perl/Monks$ perl -Mstrict -Mwarnings -E ' my @dateStrs = ( q{Fri May 8, 2020 - 11:12:13}, q{Fri May 15, 2020 - 14:08:17}, q{Sat May 16, 2020 - 7:31:22}, q{Mon Jun 1, 2020 - 6:24:18}, ); s{(?<=\D)(\d)(?=\D)}{ sprintf q{%02d}, $1 }eg for @dateStrs; say for @dateStrs;' Fri May 08, 2020 - 11:12:13 Fri May 15, 2020 - 14:08:17 Sat May 16, 2020 - 07:31:22 Mon Jun 01, 2020 - 06:24:18 #### johngg@shiraz:~/perl/Monks$ perl -Mstrict -Mwarnings -E ' my @dateStrs = ( q{Fri May 8, 2020 - 11:12:13}, q{Fri May 15, 2020 - 14:08:17}, q{Sat May 16, 2020 - 7:31:22}, q{Mon Jun 1, 2020 - 6:24:18}, q{Fri May 8, 2020 - 11:12:13}, q{Fri May 15, 2020 - 14:08:17}, q{Sat May 16, 2020 - 7:31:22}, q{Mon Jun 1, 2020 - 6:24:18}, ); s{(\s+\d)(?=\D)}{ sprintf q{ %02d}, $1 }xeg for @dateStrs; say for @dateStrs;' Fri May 08, 2020 - 11:12:13 Fri May 15, 2020 - 14:08:17 Sat May 16, 2020 - 07:31:22 Mon Jun 01, 2020 - 06:24:18 Fri May 08, 2020 - 11:12:13 Fri May 15, 2020 - 14:08:17 Sat May 16, 2020 - 07:31:22 Mon Jun 01, 2020 - 06:24:18