fix: only read from stdin if it's not a terminal #17

src/main.rs

@@ -3,7 +3,7 @@
 //! This binary should just take any amount of numbers and print them out formatted to some other
 //! system.
 
-use std::io::Read;
+use std::io::{IsTerminal, Read};
 use std::process::exit;
 
 use clap::{CommandFactory, Parser};
@@ -16,7 +16,9 @@ fn main() {
     // try to read from stdin first, appending the numbers we read to the FormatOptions
     let mut options = FormatOptions::parse();
     let mut stdin_nums = Vec::new();
-    match std::io::stdin().lock().read_to_end(&mut stdin_nums) {
+    let stdin = std::io::stdin();
+    if !stdin.is_terminal() {
+        match stdin.lock().read_to_end(&mut stdin_nums) {
             Ok(_) => {
                 let whole: String = match String::from_utf8(stdin_nums) {
                     Ok(r) => r,
@@ -42,6 +44,7 @@ fn main() {
                 exit(2);
             }
         };
+    }
 
     if options.numbers().is_empty() {
         format!("{}", FormatOptions::command().render_usage());