Extracting Thunderbird Unread Emails Count

I wanted to display my unread email count in my i3bar.

I use Thunderbird as mail client
I don’t want my i3bar to query some IMAP servers

Thunderbird Persistence

Thunderbird stores all its configuration in ~/.thunderbird in different files.
The folder <profile name>/ImapMail contains non-binary *.msf files
The header of the files conveniently contains a description of the values

// <!-- <mdb:mork:z v="1.4"/> -->
< <(a=c)> // (f=iso-8859-1)
  …
  (9D=msgOffset)(9E=offlineMsgSize)
  (9F=ns:msg:db:row:scope:dbfolderinfo:all)
  (A0=ns:msg:db:table:kind:dbfolderinfo)(A1=numMsgs)(A2=numNewMsgs)
  (A3=folderSize)(A4=expungedBytes)(A5=folderDate)(A6=highWaterKey)
  (A7=mailboxName)(A8=UIDValidity)(A9=totPendingMsgs)
  (AA=unreadPendingMsgs)(AB=expiredMark)(AC=version)(AD=forceReparse)
  (AE=fixedBadRefThreading)(AF=onlineName)(B0=MRUTime)(B1=sortType)
  (B2=sortOrder)(B3=viewFlags)(B4=viewType)(B5=sortColumns)
  (B6=columnStates)(B7=highestModSeq)>
<(582=d7)(1748=5af2bafa)(81=0)(80=1)>
…

The field A2 contains the number of new (unread) messages in hexadecimal representation

Bash Magic

find ~/.thunderbird/<profile name>/ImapMail -name 'INBOX*.msf' -exec \
	sh -c " \
		echo '{}' && \
		grep '(^A2=' '{}' | \
		tail -n1 | \
		sed -r 's/.*\(\^A2=(\w+)\).*/\1/' | \
		xargs -n1 -L1 --replace=__ printf '%d\n' '0x__'" \;

This “neat” “little” bash command does the following:

Iterate over all INBOX*.msf files
Look for the last occurrence of the A2 field
Extract the value of the A2 field
Convert the value into decimal representation

It produces an overview that looks like this:

~/.thunderbird/<profile name>/ImapMail/<imap server 1>/INBOX.msf
0
~/.thunderbird/<profile name>/ImapMail/<imap server 2>/INBOX.msf
1
~/.thunderbird/<profile name>/ImapMail/<imap server 3>/INBOX.msf
~/.thunderbird/<profile name>/ImapMail/<imap server 3>-1/INBOX.msf
6
~/.thunderbird/<profile name>/ImapMail/<imap server 4>/INBOX.msf
1292

Those numbers correspond to the unread count of the Thunderbird GUI.