walkdir
=======
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.
[](https://travis-ci.org/BurntSushi/walkdir)
[](https://ci.appveyor.com/project/BurntSushi/walkdir)
[](https://crates.io/crates/walkdir)
Dual-licensed under MIT or the [UNLICENSE](http://unlicense.org).
### Documentation
[docs.rs/walkdir](https://docs.rs/walkdir/)
### Usage
To use this crate, add `walkdir` as a dependency to your project's
`Cargo.toml`:
```
[dependencies]
walkdir = "1"
```
### Example
The following code recursively iterates over the directory given and prints
the path for each entry:
```rust,no_run
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.)
```rust,no_run
use walkdir::WalkDir;
}
```
### Example: follow symbolic links
The same code as above, except `follow_links` is enabled:
```rust,no_run
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:
```rust,no_run
use walkdir::{DirEntry, WalkDir, WalkDirIterator};
fn is_hidden(entry: &DirEntry) -> bool {
entry.file_name()
.to_str()
.map(|s| s.starts_with("."))
.unwrap_or(false)
}
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
some):
* 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:
DIR=$HOME
# 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.