fmq

jq for markdown frontmatter.

Install

From releases

Download the latest binary from GitHub Releases.

From source

cargo install --path .

Usage

fmq <expression> [file]

• If file is omitted, reads from stdin
• Queries output the result to stdout
• Mutations output the modified markdown to stdout

Examples

Query

# Get a field
fmq '.title' post.md
# Hello World

# Get nested field
fmq '.author.name' post.md
# Alice

# Get array
fmq '.tags' post.md
# ["rust", "cli"]

# From stdin
cat post.md | fmq '.title'

Mutate

# Set a field
fmq '.title = "New Title"' post.md > updated.md

# Add to array
fmq '.tags += ["new-tag"]' post.md > updated.md

# Delete a field
fmq 'del(.draft)' post.md > updated.md

# Update nested field
fmq '.author.name = "Bob"' post.md > updated.md

Piping

# Query then mutate
fmq '.tags' post.md | jq '.[0]'

# Chain mutations
fmq '.title = "New"' post.md | fmq '.draft = false' > updated.md