2 unstable releases

Uses new Rust 2024

0.2.0	Apr 29, 2025
0.1.0	Apr 26, 2025

#83 in Text editors

278 downloads per month

MIT license

20KB
206 lines

file-editor

Clean, chain-friendly text-file editing for Rust • edition 2024 • v0.2.0

file-editor is a zero-dependency library that makes it painless to create, modify, and query UTF-8 text files.
All mutating methods return &mut self, so edits compose naturally:

use file_editor::Editor;

fn main() -> std::io::Result<()> {
    Editor::create("notes.txt")?               // new (or truncate existing)
        .append("Rust 🦀 is fun\n")
        .prepend("# My Notes\n")
        .insert_after("# My Notes", "========\n", true)
        .replace("fun", "blazingly fast")
        .save()?;                              // explicit flush to disk
    Ok(())
}

Opt-in regex power

By default file-editor has no dependencies.
Activate the regex feature to let every pattern-taking method accept a compiled regex::Regex:

file-editor = { version = "0.2.0", features = ["regex"] }

use file_editor::Editor;
use regex::Regex;

fn main() -> std::io::Result<()> {
    let re = Regex::new(r"token=\w+").unwrap();
    Editor::open("config.env")?
        .mask(&re, "***")      // redact every `token=…`
        .save()?;
    Ok(())
}

Feature table

Verb	Method(s)	Notes
Create / open	`Editor::create`, `Editor::open`	`create` truncates an existing file
Rename	`rename`	Renames on disk & updates the internal path
Prepend / append	`prepend`, `append`
Insert before / after	`insert_before`, `insert_after`	`same_indent` flag preserves indentation
Replace marker	`replace_marker`	Optional `same_indent`
Search pattern	`find_lines`	Returns 1-based line numbers
Erase / replace / mask	`erase`, `replace`, `mask`	Operate on all occurrences in the buffer
Save	`save`	Writes only when the buffer is dirty

Planned > streaming mode, companion CLI…

Installation

# stable crate (no regex):
cargo add file-editor

# with regex support:
cargo add file-editor --features regex

Requires Rust 1.85 or newer (edition 2024).

Workflow

Task	Command
Build	`cargo build`
Run tests & doctests	`cargo test`
Format	`cargo fmt --all`
Lint (deny warnings)	`cargo clippy --all-targets -- -D warnings`
Coverage (HTML + terminal)	`cargo llvm-cov --workspace --open` (install once: `cargo install cargo-llvm-cov`)
Generate docs	`cargo doc --no-deps --open`

CI runs the same commands on every PR (see .github/workflows/ci.yml).

Runnable examples

Everything under examples/ writes into examples/sandbox/ (ignored by Git):

Example	Demonstrates
`basic.rs`	End-to-end mini workflow
`create.rs`	`create` + `append`
`open_rename.rs`	`open` + `rename`
`prepend.rs`, `append.rs`	Header / footer insertion
`insert_before.rs`	Block insertion above a marker
`insert_after.rs`	Block insertion below a marker
`replace_marker.rs`	In-place marker replacement
`find_lines.rs`	Pattern search
`erase.rs`	Deleting fragments
`replace.rs`, `mask.rs`	Global replacements / masking

cargo run --example insert_after

Contributing

Fork & clone
cargo fmt --check && cargo clippy --all-targets -- -D warnings
Add or update tests in tests/ (use the tempfile crate)
Open a PR describing what changed and why

All contributions are released under the MIT license.

License

Dependencies

~0–510KB