process stderr.

src/main.rs

@@ -1,7 +1,7 @@
 use std::fs;
 use std::io;
 use std::path::{Path, PathBuf};
-use std::process::Command;
+use std::process::{Command, Stdio};
 use std::env;
 
 fn unar_file(path: &Path) -> io::Result<()> {
@@ -11,6 +11,7 @@ fn unar_file(path: &Path) -> io::Result<()> {
     let output = Command::new("unar")
         .current_dir(parent_dir)
         .arg(filename)
+        .stderr(Stdio::piped())
         .output();
 
     match output {
@@ -32,7 +33,7 @@ fn is_compressed(path: &Path) -> bool {
     if let Some(ext) = path.extension() {
         if let Some(ext) = ext.to_str() {
             let ext = ext.to_lowercase();
-            return ext == "zip" || ext == "rar";
+            return ext == "zip" || ext == "rar" || ext == "7z";
         }
     }