Shell Scripting - learning how to use grep, awk, and uniq

Your script shall search LOGFILE for all lines containing this string "Failed password for USERID" where USERID is either the name of a user or the word "invalid". You are to perfom the following operations . Change the word "invalid" to .Count the number of every failed password messages for each user (including ) Sort the output first by number of occurrences in descending order, then by userid in ascending order Output a header with the current date as shown below Punctuate all large numbers with commas for readability (hint: printf) Produce an HTML document on stdout with , ,

and
tags as shown below "?UNKNOWN>" should be output using the HTML characters "

Failed Login Attempts Report as of Thu Dec 25 07:00:00 MST 2014

br/> 505root 17 adm 16 ftp 10 apache 10 mail 2 backuppc 2 games 2 news 2 squid 1 bin 1 nobody 1 operator 1 smmsp 1 sshd