Exim provides a log grepping perl script which will find and group all related log lines for whatever you search for. This tool is called exigrep
and it can look for many different things, and can use regular expressions to do the matching. Examples:
# to find all emails to or from an email address
exigrep [email protected] /var/log/exim/main.log
# to find all delivered emails to an email address
exigrep '=>.*[email protected]' /var/log/exim/main.log
# if you know the specific mail queue id
exigrep 1UF3vP-0003M7-TY /var/log/exim/main.log
# to find a specific virus matches
exigrep Heuristics.Phishing.Email.SpoofedDomain /var/log/exim/main.log
It is a very powerful tool, but one caveat is that it searches the entire file from beginning to end. This will be slow or cause high load if you have very large mail logfiles or a very busy machine.