features

List OpenType features in a font.

Quick Reference

fontisan features <font> [options]

Options

Option	Description
--format FORMAT	Output format (text, yaml, json)
--script TAG	Filter by script
--language TAG	Filter by language
--detail	Show feature details

Output

Shows:

• Feature tags
• Feature names/descriptions
• Scripts that use each feature
• Lookup count

Examples

# List all features
fontisan features font.ttf

# Features for specific script
fontisan features font.ttf --script latn

# With details
fontisan features font.ttf --detail

# JSON output
fontisan features font.ttf --format json

Sample Output

OpenType Features
=================

Tag     Name                    Scripts    Lookups
------  ----------------------  ---------  -------
liga    Standard Ligatures      latn,cyrl  12
dlig    Discretionary Ligatures latn       4
kern    Kerning                 all        156
mark    Mark Positioning        all        48
mkmk    Mark to Mark            all        24
onum    Oldstyle Figures        latn       1
pnum    Proportional Figures    latn       1
tnum    Tabular Figures         latn       1
zero    Slashed Zero            latn       1

Total: 9 features

Common Feature Tags

GSUB (Substitution) Features

Tag	Name	Description
liga	Standard Ligatures	fi, fl, etc.
dlig	Discretionary Ligatures	Optional ligatures
hlig	Historical Ligatures	Archaic forms
calt	Contextual Alternates	Context-based
salt	Stylistic Alternates	Alternate glyphs
ss01-ss20	Stylistic Sets	Grouped alternates
smcp	Small Capitals	Lowercase to small caps
c2sc	Caps to Small Caps	Uppercase to small caps
onum	Oldstyle Figures	Varying height
lnum	Lining Figures	Uniform height
pnum	Proportional Figures	Varying width
tnum	Tabular Figures	Uniform width
zero	Slashed Zero	Distinguish 0/O
case	Case-Sensitive Forms	Uppercase adjustment

GPOS (Positioning) Features

Tag	Name	Description
kern	Kerning	Pair adjustments
mark	Mark Positioning	Diacritics
mkmk	Mark to Mark	Stacked diacritics
dist	Distances	Spacing
abvm	Above Marks	Positioning above
blwm	Below Marks	Positioning below

Use Cases

Check for Ligatures

fontisan features font.ttf | grep liga

Check for Small Caps

fontisan features font.ttf | grep -E "smcp|c2sc"

Compare Feature Sets

diff <(fontisan features font1.ttf) <(fontisan features font2.ttf)

Related Commands

• scripts — List supported scripts
• info — Get comprehensive font info