Understanding Threading

Threaded Mode

So-called “threads” provide a hierarchy of messages where replies are linked to their parent message(s). This organizational form is extremely useful in mailing lists where different parts of the discussion diverge. NeoMutt displays threads as a tree structure.

In NeoMutt, when a mailbox is sorted by threads, there are a few additional functions available in the index and pager modes as shown in the table below.

Thread Mode Keys

Key	Function	Description
^D	<delete-thread>	Delete all messages in the current thread
^U	<undelete-thread>	Undelete all messages in the current thread
^N	<next-thread>	Jump to the start of the next thread
^P	<previous-thread>	Jump to the start of the previous thread
^R	<read-thread>	Mark the current thread as read
Esc d	<delete-subthread>	Delete all messages in the current subthread
Esc u	<undelete-subthread>	Undelete all messages in the current subthread
Esc n	<next-subthread>	Jump to the start of the next subthread
Esc p	<previous-subthread>	Jump to the start of the previous subthread
Esc r	<read-subthread>	Mark the current subthread as read
Esc t	<tag-thread>	Toggle the tag on the current thread
Esc v	<collapse-thread>	Toggle collapse for the current thread
Esc V	<collapse-all>	Toggle collapse for all threads
P	<parent-message>	Jump to parent message in thread

Thread Tree Display

📷 Screenshot Needed

Subject: Thread tree visualisation in index

Description: The NeoMutt index screen with set sort=threads showing a mailbox (ideally a mailing list) with several threaded conversations. The tree should include at least one multi-level thread (3+ depth) with branching replies, a collapsed thread (showing the hidden message count), and a thread with a missing parent (showing the ? character). The tree-drawing characters (├─>, └─>, │) should be clearly visible.

Highlights: The reader should notice the tree structure that visually represents the parent-child reply relationships, how deeper nesting indicates sub-conversations, and the special characters (? for missing, & for hidden) that indicate thread anomalies.

In the index, the subject of threaded children messages will be prepended with thread tree characters. By default, the subject itself will not be duplicated unless $hide_thread_subject is unset. Special characters will be added to the thread tree as detailed in the table below.

Character	Description	Notes
&	hidden message	see $hide_limited and $hide_top_limited
?	missing message	see $hide_missing and $hide_top_missing
*	pseudo thread	see $strict_threads; not displayed when $narrow_tree is set
=	duplicate thread	see $duplicate_threads; not displayed when $narrow_tree is set

NeoMutt uses Unicode box-drawing characters to draw the thread tree (e.g., ├, └, │, ─). If your terminal does not support Unicode, or you prefer plain ASCII, set the $ascii_chars boolean variable to yes. This switches the tree characters to ASCII equivalents: +, +, |, and - respectively.

Collapsing Threads

Collapsing a thread displays only the first message in the thread and hides the others. This is useful when threads contain so many messages that you can only see a handful of threads on the screen. See %M in $index_format. For example, you could use %<M?(#%03M)&(%4l)> in $index_format to optionally display the number of hidden messages if the thread is collapsed. The %<char?if-part&else-part> syntax is explained in detail in the format string conditionals documentation.

Strict Threading

Technically, every reply should contain a list of its parent messages in the thread tree, but not all do. In these cases, NeoMutt groups them by subject which can be controlled using the $strict_threads variable.

Miscellaneous Functions

In addition, the index and pager menus have these interesting functions:

<check-stats> : Calculate statistics for all monitored mailboxes declared using the mailboxes command. It will calculate statistics despite $mail_check_stats being unset.

<create-alias> (default: a) : Creates a new alias based upon the current message (or prompts for a new one). Once editing is complete, an alias command is added to the file specified by the $alias_file variable for future use.

Note

NeoMutt does not read the $alias_file upon startup so you must explicitly source the file.

<check-traditional-pgp> (default: Esc P) : This function will search the current message for content signed or encrypted with PGP the “traditional” way, that is, without proper MIME tagging. Technically, this function will temporarily change the MIME content types of the body parts containing PGP data; this is similar to the <edit-type> function’s effect.

<edit-raw-message> : This command (available in the index and pager) allows you to edit the raw current message as it’s present in the mail folder. After you have finished editing, the changed message will be appended to the current folder, and the original message will be marked for deletion; if the message is unchanged it won’t be replaced.

<edit> is a synonym of this for backwards compatibility.

See also <edit-or-view-raw-message>, <view-raw-message>.

<edit> : Alias of <edit-raw-message> for backwards compatibility.

<edit-or-view-raw-message> (default: e) : This command (available in the index and pager) is the same as <edit-raw-message> if the mailbox is writable, otherwise it is the same as <view-raw-message>.

<edit-type> (default: ^E on the attachment menu, and in the pager and index menus; ^T on the compose menu) : This command is used to temporarily edit an attachment’s content type to fix, for instance, bogus character set parameters. When invoked from the index or from the pager, you’ll have the opportunity to edit the top-level attachment’s content type. On the attachment menu, you can change any attachment’s content type. These changes are not persistent, and get lost upon changing folders.

Note that this command is also available on the compose menu. There, it’s used to fine-tune the properties of attachments you are going to send.

<enter-command> (default: “:”) : This command is used to execute any command you would normally put in a configuration file. A common use is to check the settings of variables, or in conjunction with macros to change settings on the fly.

<extract-keys> (default: ^K) : This command extracts PGP public keys from the current or tagged message(s) and adds them to your PGP public key ring.

<forget-passphrase> (default: ^F) : This command wipes the passphrase(s) from memory. It is useful, if you misspelled the passphrase.

<list-reply> (default: L) : Reply to the current or tagged message(s) by extracting any addresses which match the regular expressions given by the lists or subscribe commands, but also honor any Mail-Followup-To header(s) if the $honor_followup_to configuration variable is set. In addition, the List-Post header field is examined for mailto: URLs specifying a mailing list address. Using this when replying to messages posted to mailing lists helps avoid duplicate copies being sent to the author of the message you are replying to.

<list-subscribe> : Send an email to the address specified in the List-Subscribe header as specified in RFC2369.

<list-unsubscribe> : Send an email to the address specified in the List-Unsubscribe header as specified in RFC2369.

<pipe-message> (default: |)

Asks for an external Unix command and pipes the current or tagged message(s) to it. The variables $pipe_decode, $pipe_decode_weed, $pipe_split, $pipe_sep and $wait_key control the exact behavior of this function.

<resend-message> (default: Esc e) : NeoMutt takes the current message as a template for a new message. This function is best described as “recall from arbitrary folders”. It can conveniently be used to forward MIME messages while preserving the original mail structure. Note that the amount of headers included here depends on the value of the $weed variable.

This function is also available from the attachment menu. You can use this to easily resend a message which was included with a bounce message as a message/rfc822 body part.

<shell-escape> (default: !) : Asks for an external Unix command and executes it. The $wait_key can be used to control whether NeoMutt will wait for a key to be pressed when the command returns (presumably to let the user read the output of the command), based on the return status of the named command. If no command is given, an interactive shell is executed.

<skip-headers> (default: H) : This function will skip to the first line of the body, past the headers of the current message, regardless of current position.

<view-raw-message> : This command (available in the index and pager) opens the raw message read-only in an editor. This command does not allow editing the message, use <edit-raw-message> for this.

See also <edit-raw-message>, <edit-or-view-raw-message>.

<skip-quoted> (default: S) : This function will make the internal pager go forward to the next segment of non-quoted body text (whether the first line of the body after headers, or following a line of quoted text), or print a message if no further unquoted text can be found.

The variable $pager_skip_quoted_context can be used to show some quoted context prior to the selected line.

<toggle-quoted> (default: T) : The pager uses the $quote_regex variable to detect quoted text when displaying the body of the message. This function toggles the display of the quoted material in the message. It is particularly useful when being interested in just the response and there is a large amount of quoted text in the way.

The variable $toggle_quoted_show_levels can be used to show some context by continuing to show that number of levels rather than hiding all quoted levels.