https://github.com/ayosec/bash-builtins.rs

A Rust crate to provide utilities to implement loadable builtins for bash.
https://github.com/ayosec/bash-builtins.rs

bash shell

Last synced: 17 days ago
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A Rust crate to provide utilities to implement loadable builtins for bash.

• Host: GitHub
• URL: https://github.com/ayosec/bash-builtins.rs
• Owner: ayosec
• License: apache-2.0
• Created: 2021-08-12T01:40:07.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2024-03-18T20:17:57.000Z (8 months ago)
• Last Synced: 2024-10-29T08:28:27.221Z (18 days ago)
• Topics: bash, shell
• Language: Rust
• Homepage:
• Size: 109 KB
• Stars: 15
• Watchers: 4
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# bash-builtins

A Rust crate to provide utilities to implement loadable builtins for bash.

See the [API documentation](https://docs.rs/bash-builtins) for a detailed

explanation on how to use this crate.

## Example

See the [`examples` directory](./examples/) for more examples.

```rust

//! Bash builtin to implement a counter.

use bash_builtins::{builtin_metadata, Args, Builtin, BuiltinOptions, Result};

use std::io::{stdout, Write};

builtin_metadata!(

    name = "counter",

    create = Counter::default,

    short_doc = "counter [-r] [-s value] [-a value]",

    long_doc = "

        Print a value, and increment it.

        Options:

          -r\tReset the value to 0.

          -s\tSet the counter to a specific value.

          -a\tIncrement the counter by a value.

    ",

);

#[derive(BuiltinOptions)]

enum Opt {

    #[opt = 'r']

    Reset,

    #[opt = 's']

    Set(isize),

    #[opt = 'a']

    Add(isize),

}

#[derive(Default)]

struct Counter(isize);

impl Builtin for Counter {

    fn call(&mut self, args: &mut Args) -> Result<()> {

        // No options: print the current value and increment it.

        if args.is_empty() {

            // Use writeln!() instead of println!() to avoid

            // panicking if stdout is closed.

            writeln!(stdout(), "{}", self.0)?;

            self.0 += 1;

            return Ok(());

        }

        // Parse options. They can change the value of the counter, but the

        // updated value is stored only if we don't get any error.

        let mut value = self.0;

        for opt in args.options() {

            match opt? {

                Opt::Reset => value = 0,

                Opt::Set(v) => value = v,

                Opt::Add(v) => value += v,

            }

        }

        // It is an error if we receive free arguments.

        args.finished()?;

        // Update the state and exit.

        self.0 = value;

        Ok(())

    }

}

```

# License

This crate is released under the terms of Apache License 2.0, which is

compatible with GPLv3.

See  for more

information about the compatibility.