6 releases
Uses old Rust 2015
0.2.2 | Apr 24, 2022 |
---|---|
0.2.1 | Sep 16, 2018 |
0.1.2 | Sep 15, 2018 |
#5 in #spawned
39 downloads per month
52KB
1.5K
SLoC
U-Bend
This is a small crate that lets you build pipe chains between spawned processes using a syntax similar to the Unix shell.
#[macro_use] extern crate ubend;
use ubend::IntoPipeSetup;
let output = ubend!(
cat <"./tests/input.txt" |
grep "spam" |
wc "-l"
).expect("spawn failed").
output().
expect("reading output failed").
stdout;
let output = String::from_utf8(output).
expect("UTF-8 error").
trim().
parse::<i64>().
unwrap();
println!("output: {}", output);
Note that arguments to commands need always to be quoted. If you don't quote
them they are interpreted as Rust identifiers which allows you to pass
dynamic strings. Also FOO="bar" cat <"baz"
is the same as
FOO = "bar" cat < "baz"
, since whitespace is ignored in Rust.
use ubend::IntoPipeSetup
is needed when passing a file name or
std::fs::File
as redirection source/target.
Note: Currently only Linux ist tested. Other Unix operating systems might work, too. Windows support is not implemented.
More Examples
#[macro_use] extern crate ubend;
use ubend::IntoPipeSetup;
use ubend::PipeSetup::*;
use std::fs::File;
use std::io::{Read, Seek, SeekFrom};
// Ignore stderr
ubend!(rm "no_such_file" 2>Null);
// Redirect stderr to stdout
ubend!(rm "no_such_file" 2>&1);
// Write stderr to stderr of this process
ubend!(rm "no_such_file" 2>Inherit);
// Read from a file opened in Rust
let file = File::open("./tests/input.txt").
expect("couldn't open file");
ubend!(grep "spam" <file);
// Write stderr to a temp file
let mut chain = ubend!(rm "no_such_file" 2>Temp).
expect("spawn failed");
chain.wait_last().
expect("wait failed");
let mut temp = chain.stderr().unwrap();
// Since the file descriptor was shared with the spawned process the
// position needs to be reset manually:
temp.seek(SeekFrom::Start(0)).
expect("seek failed");
Dependencies
~43KB