fop(1): fixes glaring issue with newline handling

src/fop.rs

@@ -71,7 +71,7 @@ fn main() {
 
 	let mut buf = String::new();
 	if let Err(e) = stdin().read_to_string(&mut buf) {
-		eprintln!("{}: {}", argv[0], e.strerror);
+		eprintln!("{}: {}", argv[0], e.strerror());
 		exit(EX_IOERR);
 	};
 
@@ -79,7 +79,7 @@ fn main() {
 	let mut fields = buf.split(&d).collect::<Vec<&str>>();
 
 	/* collect arguments for the operator command */
-	let opts = argv
+	let command_args = argv
 		.iter()
 		.clone()
 		.skip(command_arg + 1) /* skip the command name */
@@ -87,7 +87,7 @@ fn main() {
 
 	/* spawn the command to operate on the field */
 	let mut spawned = Command::new(operator)
-		.args(opts) /* spawn with the specified arguments */
+		.args(command_args) /* spawn with the specified arguments */
 		.stdin(Stdio::piped())
 		.stdout(Stdio::piped()) /* piped stdout to handle output ourselves */
 		.spawn()
@@ -120,8 +120,13 @@ fn main() {
 	/* get the output with which the original field will be replaced */
 	let mut replace = output.stdout.clone();
 
-	/* as long as it’s not a newline, set the replacement to the output */
+	/* pop trailing newline out if the input did not contain it */
-	if replace.pop() != Some(b'\n') { replace = output.stdout; }
+	if fields[index].chars().last() != Some('\n') /* no newline */
+		&& replace.pop() != Some(b'\n') { /* pop last char of replacement */
+		/* restore replacement to original command output if popped char was not
+		 * a newline */
+		replace = output.stdout;
+	}
 
 	/* convert the output of the program to UTF-8 */
 	let new_field = String::from_utf8(replace).unwrap_or_else(|e| {