# IO Arg
Conviniently accept either standard streams or file paths in CLI tools written in Rust as arguments.
## Usage
```rust
use io_arg::IoArg;
use structopt::StructOpt;
/// A command line tool taking a required input argument and an optional output argument.
#[derive(Debug, StructOpt)]
struct Cli {
/// Path to input file. Set to "-" to use STDIN instead of a file.
input: IoArg,
/// Path to output file. Leave out or set to "-" to use STDOUT instead of a file.
#[structopt(long, short = "o", default_value = "-")]
output: IoArg,
}
```