fmql

Query and manage files using a SQL-like language

TLDR

Find every text file in a directory

$ fmql sql "[SELECT * FROM ~/Documents WHERE extension = 'txt']"

Recurse into subdirectories

$ fmql sql "[WITH RECURSIVE SELECT name, size FROM ~/projects WHERE extension = 'rs']"

Find large recently-modified images

$ fmql sql "[SELECT * FROM ~/Pictures WHERE (extension = 'jpg' OR extension = 'png') AND size > 1000000 AND modified > '2026-01-01']"

Sort results by size, descending

$ fmql sql "[SELECT name, size FROM ~/Downloads ORDER BY size DESC]"

Match filenames with a regular expression

$ fmql sql "[SELECT * FROM ~/logs WHERE name REGEXP '^app-[0-9]+\\.log$']"

Update permissions on every shell script under a directory

$ fmql sql "[UPDATE ~/scripts SET permissions = '755' WHERE extension = 'sh']"

PARAMETERS

sql QUERY

Execute a SQL-like query against the filesystem.

QUERY LANGUAGE

SELECT columns FROM path [WHERE condition] [ORDER BY column [ASC|DESC]]

Match files in path and return selected attributes.

WITH RECURSIVE SELECT columns FROM path ...

Same as SELECT but descends into subdirectories.

UPDATE path SET attribute = value WHERE condition

Modify file attributes (currently permissions and similar mutable metadata) on every matching file.

QUERYABLE ATTRIBUTES

name

Filename, including extension.

extension

File extension without the dot.

size

Size in bytes.

modified

Last-modified timestamp; comparable to ISO-8601 date strings.

permissions

Unix permission bits as an octal or symbolic string.

executable

Boolean: whether the file has the executable bit set.

OPERATORS

$ =    !=    <    >    <=    >=
LIKE        SQL-style wildcard match (% and _)
REGEXP      Regular-expression match
AND   OR   NOT

fmql is a small Rust experiment — its SQL dialect is "sort of" SQL, not a full query engine. Queries that look valid in a real RDBMS may be rejected. Operations are performed serially on the local filesystem, so recursive queries against very large trees can be slow. UPDATE modifies real files; test with SELECT first and back up before changing permissions in bulk.

HISTORY

fmql was written by Chris Mann (chriswmann) in Rust and published at github.com/chriswmann/fmql and on crates.io as the fmql crate. It was created as a learning exercise around combining SQL parsing with filesystem operations.