walkdir 2.2.4

Recursively walk a directory.
A cross platform Rust library for efficiently walking a directory recursively.
Comes with support for following symbolic links, controlling the number of
open file descriptors and efficient mechanisms for pruning the entries in the
directory tree.

[![Linux build status](https://api.travis-ci.org/BurntSushi/walkdir.svg)](https://travis-ci.org/BurntSushi/walkdir)
[![Windows build status](https://ci.appveyor.com/api/projects/status/github/BurntSushi/walkdir?svg=true)](https://ci.appveyor.com/project/BurntSushi/walkdir)

Dual-licensed under MIT or the [UNLICENSE](http://unlicense.org).

### Documentation


### Usage

To use this crate, add `walkdir` as a dependency to your project's

walkdir = "2"

### Example

The following code recursively iterates over the directory given and prints
the path for each entry:

use walkdir::WalkDir;

for entry in WalkDir::new("foo") {
    let entry = entry.unwrap();
    println!("{}", entry.path().display());

Or, if you'd like to iterate over all entries and ignore any errors that may
arise, use `filter_map`. (e.g., This code below will silently skip directories
that the owner of the running process does not have permission to access.)

use walkdir::WalkDir;

for entry in WalkDir::new("foo").into_iter().filter_map(|e| e.ok()) {
    println!("{}", entry.path().display());

### Example: follow symbolic links

The same code as above, except `follow_links` is enabled:

use walkdir::WalkDir;

for entry in WalkDir::new("foo").follow_links(true) {
    let entry = entry.unwrap();
    println!("{}", entry.path().display());

### Example: skip hidden files and directories efficiently on unix

This uses the `filter_entry` iterator adapter to avoid yielding hidden files
and directories efficiently:

use walkdir::{DirEntry, WalkDir};

fn is_hidden(entry: &DirEntry) -> bool {
         .map(|s| s.starts_with("."))

let walker = WalkDir::new("foo").into_iter();
for entry in walker.filter_entry(|e| !is_hidden(e)) {
    let entry = entry.unwrap();
    println!("{}", entry.path().display());

### Motivation

`std::fs` has an unstable `walk_dir` implementation that needed some design
work. I started off on that task, but it quickly became apparent that walking
a directory recursively is quite complex and may not be a good fit for `std`
right away.

This should at least resolve most or all of the issues reported here (and then

* https://github.com/rust-lang/rust/issues/27707
* https://github.com/rust-lang/rust/issues/23715

### Performance

The short story is that performance is comparable with `find` and glibc's
`nftw` on both a warm and cold file cache. In fact, I cannot observe any
performance difference after running `find /`, `walkdir /` and `nftw /` on my
local file system (SSD, ~3 million entries). More precisely, I am reasonably
confident that this crate makes as few system calls and close to as few
allocations as possible.

I haven't recorded any benchmarks, but here are some things you can try with a
local checkout of `walkdir`:

# The directory you want to recursively walk:

# If you want to observe perf on a cold file cache, run this before *each*
# command:
sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'

# To warm the caches
find $DIR

# Test speed of `find` on warm cache:
time find $DIR

# Compile and test speed of `walkdir` crate:
cargo build --release --example walkdir
time ./target/release/examples/walkdir $DIR

# Compile and test speed of glibc's `nftw`:
gcc -O3 -o nftw ./compare/nftw.c
time ./nftw $DIR

# For shits and giggles, test speed of Python's (2 or 3) os.walk:
time python ./compare/walk.py $DIR

On my system, the performance of `walkdir`, `find` and `nftw` is comparable.