> In fact, you can just look at the msgid.cahe file and see that it contains
> only message IDs in plain text without line breaks. (If it had line
breaks,
> 'wc -l msgid.cache' would tell you how many messages were there.)
There are also null bytes between them -- I think a double null where
the next one is supposed to be written.
I didn't realize that, but because of it (as another person pointed out
to me) the following works:
strings msgid.cache | wc -l
and shows that my cache of 8231 bytes contains 210 message IDs.
BTW, I changed the 8192 in my .procmailrc to 5000 but the file is not
shortened.