Q: How can I search for messages in all folders or in a selection of folders?

I addition to the quicksearch, that allows filtering out messages in folders
recursively, you can use `mairix` to do global searches in Claws Mail.

To illustrate this topic, we'll detail the necessary steps to make a global search
in a MH config (in our example, ~/Mail).

- install mairix from http://www.rpcurnow.force9.co.uk/mairix/. mairix is a program
for indexing and searching email messages stored in Maildir, MH or mbox folders.

- create a folder in Claws Mail where the search results will be stored in (in
our example: ~/Mail/Search).

- create a mairix config file (~/.mairixrc for instance):

 base=~/Mail
 mh=*
 omit=drafts:queue:trash:Junk:Search
 database=~/.mairix_db
 mfolder=Search
 mformat=mh

in that example, the root of all folders to search in is our MH storage location
(~/Mail), search will omit drafts, queue, trash, Junk and Search folders located
in ~/Mail, and will place results into the Search folder.

See `man mairix` for more information about the mairix configuration file.

- add an action in Claws Mail to start the mairix search:

 > ~/.claws-mail/tools/mairix.sh ~/.mairixrc

make sure that you've installed mairix.sh from the Tools pages (http://www.claws-mail.org/tools/claws-mail-mairix.tar.gz)
into ~/.claws-mail/tools or wherever you want, provided that you set the correct
path in the action text.

Now call the action. You'll be asked for a text to search. Search results - symlinks
to the existing message files, will be placed into the target folder, making it like
a virtual folder. Removing messages from that folder will NOT remove the original message files.

You can create as many mairix config files as you want (be sure that you set a
different database value in each of them), then create the corresponding actions
that call mairix.sh with the config filename in parameter.