Conditional Expandos — Step by Step

Conditional expandos let a format string display different text depending on whether an expando has a value. This tutorial builds up from simple cases to practical real-world configurations.

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Step 1 — The Simplest Conditional

A conditional tests an expando and shows text only when it is “true.”

An expando is true when:

• A numeric expando is non-zero (e.g. attachment count > 0)

• A string expando is non-empty (e.g. subject is set)

An expando is false when:

• A numeric expando is zero

• A string expando is empty

Syntax

%<X?true-text>

• %< opens the conditional

• X is the expando to test

• ? separates the condition from the true-text

• > closes the conditional

Example

Show “Flagged” only if the message is flagged (%F is non-zero):

set index_format = "%C %<F?Flagged> %s"

Message state	Result
Flagged	42 Flagged Meeting notes
Not flagged	42  Meeting notes

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Step 2 — Adding an Else Clause

The & separator adds a false-text branch.

Syntax

%<X?true-text&false-text>

Example

Show “Flagged” or “Normal”:

set index_format = "%C %<F?Flagged&Normal> %s"

Message state	Result
Flagged	42 Flagged Meeting notes
Not flagged	42 Normal Meeting notes

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Step 3 — Using Expandos Inside Branches

The true-text and false-text can contain any expandos, not just literal text.

Example

If there are attachments, show the count; otherwise show nothing:

set index_format = "%C %s %<X?[%X att]>"

Attachments	Result
3	42 Meeting notes [3 att]
0	42 Meeting notes

Show the count or a dash:

set index_format = "%C %s %<X?%X&->"

Attachments	Result
3	42 Meeting notes 3
0	42 Meeting notes -

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Step 4 — Formatting the Conditional Output

A format specifier before the < applies to the entire output of the conditional (whichever branch is taken), not to the condition itself.

Syntax

%[format]<X?true-text&false-text>

Example

Left-justify the result in 10 columns:

set index_format = "%C %-10<F?Flagged&Normal> %s"

Message state	Result (padded to 10)
Flagged	42 Flagged    Meeting notes
Not flagged	42 Normal     Meeting notes

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Step 5 — Old Style Syntax

NeoMutt also supports the original Mutt conditional syntax using ? delimiters:

%?X?true-text&false-text?

This is equivalent to the new style %<X?true-text&false-text>.

Comparison

New style	Old style
%<F?Flagged>	%?F?Flagged?
%<F?Flagged&Normal>	%?F?Flagged&Normal?
%<X?%X att&no att>	%?X?%X att&no att?

Both styles work identically. The new style (< >) is recommended for readability.

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Step 6 — Conditional Dates

Date expandos support time-based conditions. Instead of testing whether a value exists, they test whether a date falls within a time period.

Syntax

%<[Np?true-text&false-text>

• N is a number (optional; if omitted, means “this” period)

• p is a period character:

Period	Meaning
y	Year
m	Month
w	Week
d	Day
H	Hour
M	Minute

How It Works

• %<[1d?...> — true if the message date is within the last 1 day

• %<[2w?...> — true if the message date is within the last 2 weeks

• %<[d?...> — true if the message date is “today” (this day)

• %<[m?...> — true if the message date is “this month”

• %<[y?...> — true if the message date is “this year”

Example

Show time for today’s messages, date for older ones:

set index_format = "%C %<[1d?%[%H:%M]&%[%b %d]> %-20.20n %s"

Message date	Result
Today, 14:30	42 14:30 Alice Jones Meeting notes
March 15	42 Mar 15 Alice Jones Meeting notes

A three-level date display:

set index_format = "%C %<[1d?%[%H:%M]&%<[1y?%[%b %d]&%[%Y-%m]>> %-20.20n %s"

Message date	Result
Today	42 14:30 ...
This year	42 Mar 15 ...
Older	42 2023-06 ...

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Step 7 — Nesting Conditionals

Conditionals can be nested inside each other’s branches.

Example

Two-level nesting: if flagged, show the flag; then if new, add a marker:

set index_format = "%C %<F?%<N?F+N&F>&%<N?N& >> %s"

State	Result
Flagged + New	42 F+N Meeting notes
Flagged only	42 F Meeting notes
New only	42 N Meeting notes
Neither	42   Meeting notes

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Step 8 — Practical Configurations

A Complete $index_format

set index_format = "%4C %Z %<[1d?%[%H:%M]&%<[1y?%[%b %d]&%[%Y-%m]>> %-20.20n %<M?(%M)&   > %s %> %<X?[%X]>"
#                   |    |  |                                         |          |           |       |
#                   |    |  |                                         |          |           |       attachment count (if any)
#                   |    |  |                                         |          |           padding
#                   |    |  |                                         |          thread count (if collapsed)
#                   |    |  |                                         author name
#                   |    |  smart date (time/date/year-month)
#                   |    combined flags
#                   message number

A Status Bar with Conditionals

set status_format = "%f [Msgs:%m%<n? New:%n>%<d? Del:%d>%<F? Flag:%F>] %> (%P)"

This shows New/Del/Flag counts only when non-zero:

State	Result
5 new, 2 flagged	INBOX [Msgs:42 New:5 Flag:2] (50%)
No new, no flags	INBOX [Msgs:42] (50%)

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Quick Reference

Syntax

Style	True only	True + False
New	%<X?true>	%<X?true&false>
Old	%?X?true?	%?X?true&false?
Date	%<[Np?true>	%<[Np?true&false>
Formatted	%-10<X?true&false>

Truthiness

Type	True	False
Number	Non-zero	Zero
String	Non-empty	Empty
Date condition	Within period	Outside period

Date Period Characters

Char	Period
y	Year
m	Month
w	Week
d	Day
H	Hour
M	Minute