gistfile1.txt

[root@ip-10-0-0-142 ec2-user]# zgrep --no-filename 'sshd.*Invalid user' /var/log/secure* | cut -d' ' -f-2 | sort | uniq -c       1407 Dec
     31 Dec 10
    797 Dec 11
     88 Dec 12
     15 Dec 13
    161 Dec 14
     45 Dec 15
    300 Dec 16
    179 Dec 17
     52 Dec 18
     12 Nov 13
    626 Nov 14
    770 Nov 15
    296 Nov 16
    177 Nov 17
    185 Nov 18
    654 Nov 19
     69 Nov 20
    286 Nov 21
    194 Nov 22
     43 Nov 23
     64 Nov 24
     63 Nov 25
    122 Nov 26
    174 Nov 27
    275 Nov 28
    164 Nov 29
    336 Nov 30