gistfile1.txt

fredemmott@fredemmott-fbmbp foo % echo -en "" | ./target/debug/foo
fredemmott@fredemmott-fbmbp foo % echo -en "\n" | ./target/debug/foo
Line: ''
fredemmott@fredemmott-fbmbp foo % echo -en "foo" | ./target/debug/foo
Line: 'foo'
fredemmott@fredemmott-fbmbp foo % echo -en "foo\n" | ./target/debug/foo
Line: 'foo'
fredemmott@fredemmott-fbmbp foo % echo -en "" | ./a.out
fredemmott@fredemmott-fbmbp foo % echo -en "\n" | ./a.out
Line: ''
fredemmott@fredemmott-fbmbp foo % echo -en "foo" | ./a.out
Line: 'foo'
fredemmott@fredemmott-fbmbp foo % echo -en "foo\n" | ./a.out
Line: 'foo'

main.rs

use std::io::prelude::*;
use std::io::BufReader;
use std::fs::File;

fn main() -> std::io::Result<()> {
    let mut reader = BufReader::new(std::io::stdin());
    for line in reader.lines() {
        println!("Line: '{}'", &line?);
    }
    Ok(())
}

test.c

#include <stdio.h>
int main() {
  char buf[1024];
  while (gets(buf)) {
    printf("Line: '%s'\n", buf);
  }
  return 0;
}