add terminal check

Cargo.toml

@@ -5,5 +5,7 @@ authors = ["Hatter Jiang <jht5945@gmail.com>"]
 edition = "2018"
 
 [dependencies]
+libc = "0.2.65"
 term = "0.5.2"
 term_size = "0.3.1"
+lazy_static = "1.3.0"

src/lib.rs

@@ -1,3 +1,5 @@
+#[macro_use]
+extern crate lazy_static;
 extern crate term;
 
 use std::{

src/util_msg.rs

@@ -2,19 +2,33 @@ use std::{
     io::{self, Write},
 };
 
+lazy_static! {
+    pub static ref IS_ATTY: bool = is_atty();
+}
+
 pub enum MessageType { INFO, OK, WARN, ERROR, DEBUG, }
 
+pub fn is_atty() -> bool{
+    let isatty = unsafe { libc::isatty(libc::STDOUT_FILENO as i32) } != 0;
+    isatty
+}
+
 pub fn print_color(color: Option<term::color::Color>, is_bold: bool, m: &str) {
     let mut t = term::stdout().unwrap();
-    match color {
+    match *IS_ATTY {
-        Some(c) => t.fg(c).unwrap(),
+        true => {
-        None => (),
+            match color {
-    }
+                Some(c) => t.fg(c).unwrap(),
-    if is_bold {
+                None => (),
-        t.attr(term::Attr::Bold).unwrap();
+            }
-    }
+            if is_bold {
-    write!(t, "{}", m).unwrap();
+                t.attr(term::Attr::Bold).unwrap();
-    t.reset().unwrap();
+            }
+            write!(t, "{}", m).unwrap();
+            t.reset().unwrap();
+        },
+        false => write!(t, "{}", m).unwrap(),
+    };
 }
 
 pub fn print_color_and_flush(color: Option<term::color::Color>, is_bold: bool, m: &str) {