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Transform Message Display

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Transform Message Display#

Display Munging#

Working within the confines of a console or terminal window, it is often useful to be able to modify certain information elements in a non-destructive way — to change how they display, without changing the stored value of the information itself. This is especially so of message subjects, which may often be polluted with extraneous metadata that either is reproduced elsewhere, or is of secondary interest.

Usage:

subject-regex regex replacement
unsubject-regex { * | regex }

Note

Before 2026-01-13, these commands were called subjectrx and unsubjectrx.

:subject-regex specifies a regular expression which, if detected in a message subject, causes the subject to be replaced with the “replacement” value. The replacement is subject to substitutions in the same way as for the spam command: %L for the text to the left of the match, %R for text to the right of the match, and %1 for the first subgroup in the match (etc). If you simply want to erase the match, set it to %L%R. Any number of :subject-regex commands may coexist.

Important

The “replacement” value replaces the entire subject, not just the match!

:unsubject-regex removes a given subject-regex from the substitution list. If * is used as the argument, all substitutions will be removed.

Example: Subject Munging

# Erase [rt #12345] tags from Request Tracker (RT) e-mails
subject-regex '\[rt #[0-9]+\] *' '%L%R'
# Servicedesk is another RT that sends more complex subjects.
# Keep the ticket number.
subject-regex '\[servicedesk #([0-9]+)\] ([^.]+)\.([^.]+) - (new|open|pending|update) - ' '%L[#%1] %R'
# Strip out annoying [listname] prefixes in subjects
subject-regex '\[[^]]*\]:? *' '%L%R'

📷 Screenshot Needed

Subject: Index with transformed subject lines

Description: NeoMutt index view showing messages from a mailing list where :subject-regex rules have been applied — the [listname] prefixes and [rt #12345] tags are stripped from subject lines, leaving clean, readable subjects. Ideally a before/after comparison.

Highlights: The cleaner subject column after munging — list prefixes and ticket-system tags are gone, making subjects easier to scan in the index.

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