sudo(8) cat(1) %2Fvar%2Flog%2Fauth.log %7C grep -oEi %22Invalid user %28%5Ba-zA-Z0-9%5D%2B%29%22 %7C colrm 1 13 %7C uniq -c %7C sort -h
execute a command as another user
concatenate files and print on the standard output
Concatenate FILE(s), or standard input, to standard output.

With no FILE, or when FILE is -, read standard input.
-E, --show-ends
       display $ at end of each line
source manpages: sudocat