GNUmakefile, fop(1): added sysexits support

src/fop.rs

@@ -18,13 +18,18 @@
 
 use std::{
 	env::args,
-	io::{ Read, stdin, Write },
+	io::{ stdin, Write },
 	process::{ Command, exit, Stdio },
 };
 
+extern crate sysexits;
+use sysexits::EX_USAGE;
+
 fn main() {
 	let argv = args().collect::<Vec<String>>();
 
+	let usage = format!("Usage: {} index command [args...]", argv[0]);
+
 	let index = match argv.get(1) {
 		Some(i) => {
 			i.parse::<usize>().unwrap_or_else(|_| {
@@ -33,18 +38,18 @@ fn main() {
 			})
 		},
 		None => {
-			eprintln!("Usage: {} index command args...", argv[0]);
-			exit(1);
+			eprintln!("{}", usage);
+			exit(EX_USAGE);
 		},
 	};
 
 	let mut buf = String::new();
-	stdin().read_to_string(&mut buf).unwrap();
+	stdin().read_line(&mut buf).unwrap();
 	let mut fields = buf.split('␞').collect::<Vec<&str>>();
 
 	argv.get(2).unwrap_or_else(|| {
-		eprintln!("Usage: {} index command args...", argv[0]);
-		exit(1);
+		eprintln!("{}", usage);
+		exit(EX_USAGE);
 	});
 
 	let opts = argv.iter().clone().skip(3).collect::<Vec<&String>>();
@@ -57,7 +62,11 @@ fn main() {
 		.unwrap();
 
 	let field = fields.get(index).unwrap_or_else(|| {
-		eprintln!("{}: {}: No such index in input.", argv[0], index.to_string());
+		eprintln!(
+			"{}: {}: No such index in input.",
+			argv[0],
+			index.to_string()
+		);
 		exit(1);
 	});