64 lines
2.0 KiB
Markdown
64 lines
2.0 KiB
Markdown
# duct.rs [](https://github.com/oconnor663/duct.rs/actions) [](https://crates.io/crates/duct) [](https://docs.rs/duct)
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Duct is a library for running child processes. Duct makes it easy to build
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pipelines and redirect IO like a shell. At the same time, Duct helps you
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write correct, portable code: whitespace is never significant, errors from
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child processes get reported by default, and a variety of [gotchas, bugs,
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and platform
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inconsistencies](https://github.com/oconnor663/duct.py/blob/master/gotchas.md)
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are handled for you the Right Way™.
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- [Documentation](https://docs.rs/duct)
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- [Crate](https://crates.io/crates/duct)
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- [GitHub repo](https://github.com/oconnor663/duct.rs)
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- [the same library, in Python](https://github.com/oconnor663/duct.py)
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Examples
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--------
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Run a command without capturing any output. Here "hi" is printed directly
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to the terminal:
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```rust
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use duct::cmd;
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cmd!("echo", "hi").run()?;
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```
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Capture the standard output of a command. Here "hi" is returned as a
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`String`:
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```rust
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let stdout = cmd!("echo", "hi").read()?;
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assert_eq!(stdout, "hi");
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```
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Capture the standard output of a pipeline:
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```rust
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let stdout = cmd!("echo", "hi").pipe(cmd!("sed", "s/i/o/")).read()?;
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assert_eq!(stdout, "ho");
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```
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Merge standard error into standard output and read both incrementally:
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```rust
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use duct::cmd;
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use std::io::prelude::*;
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use std::io::BufReader;
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let big_cmd = cmd!("bash", "-c", "echo out && echo err 1>&2");
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let reader = big_cmd.stderr_to_stdout().reader()?;
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let mut lines = BufReader::new(reader).lines();
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assert_eq!(lines.next().unwrap()?, "out");
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assert_eq!(lines.next().unwrap()?, "err");
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```
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Children that exit with a non-zero status return an error by default:
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```rust
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let result = cmd!("false").run();
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assert!(result.is_err());
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let result = cmd!("false").unchecked().run();
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assert!(result.is_ok());
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```
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