Customize your mail environment with the light and powerful Claws Mail

Flexible Claws


Sharpen your claws on this powerful and highly configurable email client.

By Paul Mangan

LennyLT, photocase.com

Claws Mail [1] started in early 2001 as Sylpheed-Claws, the development version of Sylpheed [2]. Sylpheed-Claws provided a testbed for a handful of enthusiastic Sylpheed contributors and users to test patches. Because many stable and useful features were not finding their way into Sylpheed, Sylpheed-Claws evolved on its own and was later renamed Claws Mail. A small team of enthusiastic programmers continues to develop Claws Mail, which has grown into a robust, user-friendly email client.

Claws Mail is a standards-compliant, desktop-neutral email client and newsreader with a GTK+ interface [3] released under the GPL license. This lightweight mail reader is highly configurable and offers some unique and powerful customization features.

Claws Mail provides message filtering, as well as templates, tags, support for GnuPG, RSS feed reading, HTML rendering, calendaring, and more.

Getting Started

When you run Claws Mail for the first time, the setup wizard provides a short series of dialogs for setting up a POP, IMAP, or Local account. If you have previously used Sylpheed, the wizard will import your settings.

The wizard also includes a special Template feature (described later in this article) that system administrators can use for rapid deployment.

Users will recognize the default look of the main window (Figure 1), which is fairly typical for email clients. The menu bar at the top displays Claws Mail functions. Folders are shown in a column on the left side; the message list appears in the top half of the screen above the current message, and the QuickSearch bar resides beneath the messages. (Claws Mail also offers four other layouts to suit different tastes and screen sizes.)

Figure 1: The Claws Mail Main Window.

Toolbar

The default toolbar layout allows quick access to all of the common operations, such as fetching, sending, composing, forwarding, and replying to messages. The status bar, which runs along the bottom of the window, shows information about currently running processes, such as mail retrieval and filtering. Buttons for switching between online and offline modes, as well as an account selector, are on the right, along with an attachment column that lets users easily access message attachments.

To fetch new messages, click the Get Mail button on the toolbar. Claws lets you check incoming messages for spam with one of the anti-spam plugins, and you can filter and sort the messages into subfolders.

If you would rather not click a button to check your mail, you can configure Claws to fetch your messages automatically. Use one of the notification plugins to configure automatic notification if a new messages arrives. The Claws command interface also lets you execute an arbitrary command when a message arrives, thus providing unlimited options for custom processing.

Composing

Composing a new message is as simple as clicking the Compose button on the toolbar. The message composer is equipped with spell checking, wrapping, and an undo feature. Actions and templates (described later in this article) provide additional possibilities for creating and processing messages. Claws also offers a variety of privacy options, as well as a return receipt feature and priority settings.

You can use an external editor to compose messages and insert text files directly into the body of a message.

Configuring Claws Mail

Claws Mail offers a number of options for configuring preferences and customizing the interface. The Account Preferences dialog lets the user define basic information such as email addresses, signatures, incoming and outgoing server names, and ports. You can also configure security parameters, such as SSL settings, SMTP authentication options, and GnuPG keys.

The Common Preferences dialog offers other configuration options, with which you can choose to use an external program to retrieve mail, configure colors and fonts, select an icon theme, customize the toolbars, set up external applications such as a web browser, configure plugins, and much more.

Each folder also has a smaller set of options, known as Properties, that overrule preferences set elsewhere. This feature is particularly useful if you use filtering to organize a large collection of messages into many folders. A folder can be associated with a default template, default dictionary, or a default account.

Filtering

Claws Mail comes with a filtering engine that enables matching based on any part of a received message. You can filter messages as they arrive or later. A filtering rule consists of a condition or several conditions that a message must match (Figure 2), and one or more actions, which are operations that are carried out on a matching message. A message can, for example, be matched by any header, any phrase in the body, an attachment type, a color label, whether the address is found in the address book, and so on.

Figure 2: The Filtering Condition window lets you specify filtering criteria.
Changing to Claws Mail

Claws Mail uses MH mailboxes, which means it can share mailboxes with other MUAs, such as Mutt. Claws also comes with support for the MBOX format. The Tools page of the Claws Mail website provides various scripts for converting mailboxes, address books, and filtering rules from other email applications.

Actions

Actions extend the possibilities of Claws Mail, enabling the full power of the Unix command line for processing mail. A user can decode uuencoded messages, reformat message text using external tools such as Par, or pass text selections to external tools - the only limit is the user's imagination.

The actions that are configured by the user are accessible from the /Tools/Actions/... menus of both the main and Compose windows. See the box titled "Examples of Actions" for a sample of some Claws Mail actions.

Examples of Actions

This action decodes uuencoded messages with the xdeview decoder. If an encoded file is split into multiple messages, the action decodes them all:

Menu Name: UUdeview
Command Line: xdeview %F&

This action pipes the Subject header value to a script:

Menu Name: Get Subject
Command Line: grep "^Subject:\ " %f | cut -d\ -f 2-| script.sh

This action performs a whois lookup on the selected text

Menu Name: whois
Command Line: | whois '%s'

Processing

Claws also includes a feature called processing that is similar to filtering. Processing rules are attached to a folder and can be run automatically when entering the folder.

Templates

The Claws Mail's template feature lets you predefine templates for faster and easier composition. You can use templates to fill the message headers or body with static or dynamic content. This predefined content can include symbols and settings for date elements, tags, dictionaries, account properties, and information held in the address book. Commands within templates let you automatically insert files or program output into a message.

The reply template shown in Listing 1 shows a familiar example. This template resembles the standard introduction that often accompanies a message reply. Claws Mail offers almost total flexibility to customize the text and format. In this case, the reply includes the name of the respondent (Regards, Paul) as well as a random Unix-style fortune at the end of the message.

Listing 1: A Reply Template
01 On %date
02 %from wrote:
03
04 %quoted_msg_no_sig
05
06 %cursor
07
08 Regards
09
10 Paul
11
12 --
13 |p{fortune}

Address Book

The Claws Mail address book holds information about contacts (Figure 3). The user can configure a custom attributes list, allowing quick definition of important fields.

Figure 3: Manage your contacts with the Claws Mail address book.

The data held in the address book can be used for automatic address completion in the Compose window. Address book data can be used with anti-spam plugins and whitelisting tools.

With the address book, you also can pre-fill fields used in templates. Reading and writing to LDAP servers and vCards is supported, and jPilot synchronization is supported.

QuickSearch

Claws Mail offers other useful features, such as the powerful QuickSearch tool, which allows searching through folders and sub-folders based on any criteria. QuickSearch can search in standard headers, but it also has an Extended mode, which enlists the full power of the filtering engine.

Setup Wizard for Sys Admins

System administrators can create a wizard configuration template with the correct values entered in the setup wizard, so users only need to enter their passwords. Using the configuration template, the system administrator can define the server addresses, add LDAP servers or people to the address book, add filtering rules, and load plugins.

To set up a configuration template:

  1. Start Claws Mail with a user who does not have a ~/.claws-mail directory, click through the wizard without entering any settings, and then use the Save button to exit the wizard.
  1. Quit Claws Mail.
  1. Edit the newly created wizard template file ~/.claws-mail/accountrc.tmpl and save it. The template file is fully commented with instructions and details about each entry.
  1. Delete both ~/.claws-mail/accountrc and ~/.claws-mail/folderlist.xml, then recursively copy the .claws-mail directory to /etc/skel/. If Claws Mail will use MH folders, then also copy the Mail directory to /etc/skel/. Then chown both these directories in /etc/skel/ to root:root.

Conclusion

Claws also supports user-defined hotkeys and provides good mailing list support. Several operations are available from the command line that allow interaction with external applications, such as web browsers or file managers. More than 20 plugins support features such as RSS reading, PDF display, and personal and public calendaring.

If you like a lot of control over your email, and you're looking for a powerful application that is light on resources, give Claws Mail a try.

INFO
[1] Claws Mail: http://www.claws-mail.org
[2] Sylpheed: http://sylpheed.sraoss.jp/en/
[3] GTK+, the GIMP Tool Kit: http://www.gtk.org
[4] Claws Mail User Manual: http://www.claws-mail.org/documentation.php
[5] Claws Mail plugins: http://www.claws-mail.org/plugins.php
[6] Claws Mail themes: http://www.claws-mail.org/themes.php