hello

Greets people from the command line.

Usage

Argument	Description
`NAME`	Optional. The name to greet. Only the first argument is read. Defaults to the `USER` environment variable, then to `world`.
`--shout`	Upper-cases the greeting.
`--version`	Prints the crate version and exits.
`--times N`	Prints the greeting `N` times. Defaults to 1.

$ cargo run -- Ada
Hello, Ada!

$ cargo run -- --shout Ada
HELLO, ADA!

$ cargo run -- --times 2 Ada
Hello, Ada!
Hello, Ada!

$ cargo run -- --version
0.1.0

With no name it greets whoever is signed in.

Output

$ cargo run -- Grace
Hello, Grace!

Develop

This project uses the Rust 2021 edition.

cargo test

Troubleshooting

error: --times value must be a number, got "abc"

--times needs a whole number of zero or more. If the value is anything else, such as abc, -1 or 2.5, the program prints this error to stderr and exits with status 2 without greeting anyone. Pass a plain number, for example --times 3. A --times with no value after it also fails, with --times requires a value.

The greeting says Hello, world! when I gave a name

An empty or whitespace-only name, such as cargo run -- "", is treated as no name and the greeting uses world. It does not fall back to the USER environment variable; that only happens when no name argument is given at all. Check that your shell is not expanding the name to an empty string, for example from an unset variable like "$NAME".

License

This project is licensed under the MIT License. The full license text is available at https://opensource.org/license/mit.

flagon-io/hello

README.md