Listing All Unique MailTags Keywords

After figuring out yesterday how to list all the unique MailTags projects in use, today I worked out how to list all the unique MailTags keywords in use.  As it turns out, it wasn’t as hard as I had suspected that it would be.

(Note to experienced UNIX hackers:  I’m sure that I probably could have worked out a more elegant solution involving more pipes and redirection, but this works for a UNIX apprentice such as me.)

Here are the commands I used to parse down the list of unique keywords (this command is broken across two lines, but should be typed all on one line):

mdls <path to mailbox> | grep kMDItemKeywords |
awk ‘{print $3 $4 $5 $6 $7 $8 $9}’ >> outputfile.txt

This uses the mdls command to list all the metadata from the messages in the specified directory, pipes that through grep to pick out only the lines containing “kMDItemKeywords”, then uses awk to list all the keywords (which are in a comma-delimited list surrounded by parentheses.  You’ll want to repeat this command for every mailbox you use (I have different mailboxes to archive messages by year, so I had to repeat this for 2005, 2006, etc.)

Once we have the keywords list, then we munge it:

cat outputfile.txt | tr ‘,’ ‘\n’ > outputfile2.txt
sed s/\(//g < outputfile2.txt > outputfile3.txt
sed s/\)//g < outputfile2.txt > outputfile3.txt
sort outputfile3.txt > sorted-file.txt
uniq sorted-file.txt > unique-file.txt

This replaces commas with a newline (the tr command), strips out the parentheses (the next two sed commands), then sorts it and returns only the unique values.  The end result, stored in unique-file.txt, contains a list of unique MailTags keywords used in all your mailboxes.

Useful, eh?