I wanted to locate messages from any sender at a particular domain name in the mailbox for an account on a Linux system. The server where the acount resides uses sendmail and dovecot for email and the mailbox file for the account was in mbox format. When email is stored in mbox format, all email messages in the inbox are stored in the same text file. The beginning of each email message is indicated by a line whose first five characters consist of "From" followed by a space (the so named "From_ line" or "'From ' line" or simply "From line") followed by the sender's e-mail address.
In this case, the mailbox was huge with tens of
thousands of messages in a file 24 GB in size and I wanted
to extract just a few pertinent messages. So I created find-email.py,
which can be run in either "brief" or "full" mode by changing the value
of a variable named brief in the script. In brief mode, the
script will just print the "from" line for any message where a sender's
email address matches the specified address followed by the subject of
the message and then the date the message was sent. When all messages
in the file have been processed, it will print the number of matching
messages found. In "full" mode, the script will print the entire email
message whenever a match is found.
