Sup is a powerful new mail client developed for people who manage lots of mail. It can be viewed as a cross between Mutt and Gmail, with very fast operation and search, tagging, automatic contact management, support for a wide variety of accounts at once, and more.



Sup only works with Ruby 2.3.3. Arch moved to a newer Ruby which makes sup crash. Sup is at the moment not being actively maintained to keep up with new versions of Ruby.

You can temporarily install sup using this workaround using RVM.


Sup comes with an easy to use configuration tool called sup-config. To use it, start it in the console and walk through the steps, which are as follows:

  1. Enter your full name.
  2. Enter your primary e-mail address, as well as any alternate e-mail addresses.
  3. Enter the path to your signature file, if you have one.
  4. Enter the editor that should be used to compose new mail, as well as any arguments that should be passed to it.
  5. Add sources for your mail, including:
    1. mbox files
    2. maildir directories

Support for remote sources (POP3, IMAP, IMAPS, and mbox+ssh) was removed in the 0.12 release.

Sup is for the most part only an MUA (mail user agent) and cannot handle downloading mail on its own. You can use tools like offlineimap, fetchmail, and rsync to transfer email to the local system mbox or maildir folders.

The sup wiki has an example for configuring a gmail+imap source using offlineimap. The Mutt#POP3 subsection shows some additional mail transfer methods.

After the email sources have been added, sup-config will execute the sup-sync command to import mail into your mailbox.

Filtering mail

sup works by having all relevant mail in one view at a time and no folders. To control exactly what is viewed and what is not mail needs filtering.

There are many ways to filter mail. Depending on how you access your mail you might want to filter on the serverside (with e.g. imapfilterAUR or on the clientside.

To decide which way to go consider these two scenarios:

  • you always check mail on the same computer using sup -> go for local filtering
  • you want to be able to read your (uncluttered) email (through webmail) when using other computers -> filter on the server

Local filtering

The sup hook before-add-message.rb enables you with a little ruby knowledge to filter your mail and applying labels, archive, mark read etc. to mail easily.

Filter serverside

Sup only hides from view so to keep the serverside clean you have to resort to another tool. imapfilterAUR is a popular mailfilter. Set it up starting from the example.config.

Tip: Some servers impose quotas and to keep within it you can use archivemailAUR to clear the server from old mail.

sup sources

Sup uses the file ~/.sup/sources.yaml to get sync your mail with its index and supports adding one or more labels to all mail from a source.

- !,2006-10-01/Redwood/Maildir 
  uri: maildir:/home/User/Mail/Inbox
  usual: true
  archived: false
  id: 1
  labels: []
- !,2006-10-01/Redwood/Maildir 
  uri: maildir:/home/User/Mail/Pulse
  usual: true
  archived: true
  id: 2
  - pulse
  - cruft

As seen in the example the Pulse folder has 2 labels: pulse and cruft. All the mail from Pulse is archived on import and hidden from view avoiding a cluttered screen. See the sup wiki for details on labels and ids.

Warning: The source-statements need to have unique ids to work properly.

sup hooks

sup has to types of hooks: interactive and non-interactive to enable the user to easily customize the program. See details in the sup wiki on hooks for details.

before-poll hook

To activate the filtering and syncing automatically we set up a non-interactive startup hook using before-poll:

 File: ~/.sup/hooks/before-poll.rb
 Executes immediately before a poll for new messages commences.
 No variables.

Here is a simple example (without filtering)

 say "Running offlineimap..."
 system "offlineimap", "-o", "-u", "quiet"

Here is a simple example (with filtering)

 say "Running imapfilter..."
 system "imapfilter", "-c", "path-to-config.lua"
 say "Running offlineimap..."
 system "offlineimap", "-o", "-u", "quiet"

Now running sup will start filtering and then synching mail when sup starts or whenever you poll mail manually. See details in the sup wiki on before-poll

Viewing HTML attachments

create ~/.sup/hooks/mime-decode.rb with

   require 'shellwords'
   unless sibling_types.member? "text/plain"
     case content_type
     when "text/html"
       `/usr/bin/w3m -dump -T #{content_type} #{Shellwords.escape filename}`


    require 'shellwords'
    unless sibling_types.member? "text/plain"
      case content_type
      when "text/html"
	`/usr/bin/links -dump #{Shellwords.escape filename}`

Note the difference in program executed. See details on the sup wiki

Viewing non-text attachments

Note: Install xdg-utils to use xdg-open

create ~/.sup/hooks/mime-view.rb with

# filename has already been shellesacped
  pid = Process.spawn("xdg-open", filename,
                    :out => '/dev/null',
                    :err => '/dev/null')

  Process.detach pid


See details on the sup wiki


Execute the sup command to start the Sup mail client. The program should show the messages imported by sup-config.

The most important key for new users to remember is the ? key. This will display a full list of keyboard commands at any point, reminding new users how to navigate the program.

To navigate between threads, use the arrow keys or the j and k keys (Shift+j and Shift+k work like the Page Up and Page Down keys). To jump between threads with new messages, press the Tab key. Sup doesn't load all threads by default; press Shift+m to load more (more messages will automatically load to fill the window).

To view a thread, select it and press the Enter key. To expand or collapse an individual message while viewing a thread, select the message and press the Enter key. Press Shift+n to expand only new messages (the default view) or Shift+e to toggle the state of all messages. Press o to show or hide hidden parts of a message (such as signatures).

To navigate between messages in a thread, press the n and p keys. To display the headers on a message, press the h key.

To cycle through buffers, press the b key, or press the ; key to view a list of all of the open buffers. To kill a buffer, press the x key.

To archive a thread, press the a key. This will hide it from the inbox until someone replies to it, at which point it will reappear. To kill a thread, press the & key. This is equivalent to Gmail's "mute" function, which hides a message even if people reply to it. It will never re-appear in the inbox, but it will still show up in search results.

To star a thread, press the * key. To mark a thread as spam, press the Shift+s key. Sup doesn't have any built-in spam filter; for that, consider a program such as spamassassin.

To tag a thread, press the t key. To label the messages in a thread, press the l key. To search labels, press the Shift+l key. Enter a label for which to search or press the Enter key to call up a list of labels. To perform a full text search, press the \ key.

To view a list of contacts, press the Shift+c key. To e-mail one of the people on the list, select his or her name and press the Enter key.

Back-up and Restore

Backing-up e-mail is very important. To ensure that you do not lose anything, first back up the sources, such as mbox files and maildir directories, then run:

$ sup-dump > filename

This will back-up all message states in a text file. To restore your message states from this text file, simply run:

$ sup-sync [<source>+] --restored --restore filename

Just remember that the commands above only back-up and restore message states. The messages themselves will need to be backed-up separately.

List of Keybindings

Keybindings from inbox-mode

a : Archive thread (remove from inbox)
A : Archive thread (remove from inbox) and mark read

Keybindings from thread-index-mode

   M : Load 20 more threads
  !! : Load all threads (may list a _lot_ of threads)
  ^G : Cancel current search
   @ : Refresh view         
   * : Star or unstar all messages in thread
   N : Toggle new/read status of all messages in thread
   l : Edit or add labels for a thread          
   e : Edit message (drafts only)     
   S : Mark/unmark thread as spam
   d : Delete/undelete thread    
   & : Kill thread (never to be seen in inbox again)
   $ : Save changes now                          
 tab : Jump to next new thread
   r : Reply to latest message in a thread
   f : Forward latest message in a thread 
   t : Tag/untag selected thread
   T : Tag/untag all threads
   g : Tag matching threads
+, = : Apply next command to all tagged threads
   # : Force tagged threads to be joined into the same thread
   u : Undo the previous action

Keybindings from thread-view-mode

      h : Toggle detailed header
      H : Show full message header
      V : Show full message (raw form)
<enter> : Expand/collapse or activate item
      E : Expand/collapse all messages
      e : Edit draft
      y : Send draft
      l : Edit or add labels for a thread
      o : Expand/collapse all quotes in a message
      n : Jump to next open message
      p : Jump to previous open message
      z : Align current message in buffer
      * : Star or unstar message
      N : Toggle unread/read status of message
      r : Reply to a message
      f : Forward a message or attachment
      i : Edit alias/nickname for a person
      D : Edit message as new
      s : Save message/attachment to disk
      S : Search for messages from particular people
      m : Compose message to person
      ( : Subscribe to/unsubscribe from mailing list
      ) : Subscribe to/unsubscribe from mailing list
      | : Pipe message or attachment to a shell command
     .a : Archive this thread and kill buffer
     .d : Delete this thread and kill buffer
     .s : Mark this thread as spam and kill buffer
     .N : Mark this thread as unread and kill buffer
     ,a : Archive this thread, kill buffer, and view next
     ,d : Delete this thread, kill buffer, and view next
     ,s : Mark this thread as spam, kill buffer, and view next
     ,N : Mark this thread as unread, kill buffer, and view next
     ,n : Kill buffer, and view next
     ]a : Archive this thread, kill buffer, and view previous
     ]d : Delete this thread, kill buffer, and view previous
     ]s : Mark this thread as spam, kill buffer, and view previous
     ]N : Mark this thread as unread, kill buffer, and view previous
     ]n : Kill buffer, and view previous

Keybindings from contact-list-mode

   M : Load 10 more contacts
   D : Drop contact list and reload
a, i : Edit alias/or name for contact
   t : Tag/untag current line
   + : Apply next command to all tagged items
   S : Search for messages from particular people

Keybindings from line-cursor-mode

<down arrow>, j : Move cursor down one line
  <up arrow>, k : Move cursor up one line
        <enter> : Select this item

Keybindings from scroll-mode

                        J, ^E : Down one line
                        K, ^Y : Up one line
              <left arrow>, h : Left one column
                <right arrow> : Right one column
     <page down>, <space>, ^F : Down one page
<page up>, p, <backspace>, ^B : Up one page
                           ^D : Down one half page
                           ^U : Up one half page
                 <home>, ^, 1 : Jump to top
                     <end>, 0 : Jump to bottom
                            [ : Jump to the left
                            / : Search in current buffer
                            n : Jump to next search occurrence in buffer

Global keybindings

   q : Quit Sup, but ask first
   Q : Quit Sup immediately
   ? : Show help
   b : Switch to next buffer
   B : Switch to previous buffer
   x : Kill the current buffer
   ; : List all buffers
   C : List contacts
  ^L : Redraw screen
\, F : Search all messages
   U : Show all unread messages
   L : List labels
   P : Poll for new messages
m, c : Compose new message
  ^G : Do nothing
   R : Edit most recent draft message


Crashing with: Illegal instruction (core dumped)

sup uses a search engine called Xapian which is being compiled to use SSE2 instructions. If your CPU does not support SSE2 instructions you will encounter the error message:

   Illegal instruction (core dumped)

To solve this you have to compile Xapian with the flag --disable-sse.

1. Looking at the PKGBUILD for ruby-xapian-rubyAUR you can see that it downloads a gem from Download the gem.

2. run these commands

   gem unpack xapian-ruby.gem
   gem unpack --spec xapian-ruby.gem
   mv xapian-ruby.gemspec xapian-ruby/
   cd xapian-ruby

3. You are suppose to edit the Rakefile. Your goal is to change the 2 lines where it runs the config changes. All you have to do is to append --disable-sse to the end of those configuration commands:

   system! "./configure --prefix=#{prefix} --exec-prefix=#{prefix} --disable-sse"
   system! "./configure --prefix=#{prefix} --exec-prefix=#{prefix} --with-ruby --disable-sse"

And save those changes.

4. run

   gem build xapian-ruby.gemspec
   gem install --local xapian-ruby.gem

This should solve the problem with Xapian not running on old CPUs. It should also be mentioned that if it is your first time you run sup-config and you have done everything correctly but still end up wih the error message

   This Sup version expects a v4 index, but you have an existing v0 index. Please run sup-dump to save your labels, move /home/user/.sup/xapian out of the way, and run sup-sync --restore. (RuntimeError)
   Rats, that failed. You may have to do it manually.

it is possible that you also have this issue, try to run the other executables such as sup or sup-dump to see if you get the Illegal instruction (core dumped) error message.

Tips and tricks

See also