Disable clap color on blind terminal

Cargo.toml

@@ -16,6 +16,8 @@ name = "mask"
 path = "src/lib.rs"
 
 [dependencies]
+# see https://rust-lang-nursery.github.io/cli-wg/in-depth/machine-communication.html?highlight=atty#whos-reading-this
+atty = "0.2"															# https://github.com/softprops/atty
 colored = "1.8.0"                                                       # https://github.com/mackwic/colored
 pulldown-cmark = { version = "0.5", default-features = false }          # https://github.com/raphlinus/pulldown-cmark
 

src/main.rs

@@ -1,6 +1,7 @@
 use std::env;
 use std::path::Path;
 
+use atty::{self, Stream};
 use clap::{
     crate_authors, crate_description, crate_name, crate_version, App, AppSettings, Arg, ArgMatches,
     SubCommand,
@@ -14,7 +15,11 @@ fn main() {
     let cli_app = App::new(crate_name!())
         .setting(AppSettings::VersionlessSubcommands)
         .setting(AppSettings::SubcommandRequired)
-        .setting(AppSettings::ColoredHelp)
+        .setting(if atty::is(Stream::Stdout) {
+            AppSettings::ColoredHelp
+        } else {
+            AppSettings::ColorNever // in case it run on terminal without color support
+        })
         .version(crate_version!())
         .author(crate_authors!())
         .about(crate_description!())
@@ -90,7 +95,13 @@ fn build_subcommands<'a, 'b>(
     subcommands: &'a Vec<Command>,
 ) -> App<'a, 'b> {
     for c in subcommands {
-        let mut subcmd = SubCommand::with_name(&c.name).about(c.desc.as_ref()).setting(AppSettings::ColoredHelp);
+        let mut subcmd = SubCommand::with_name(&c.name)
+            .about(c.desc.as_ref())
+            .setting(if atty::is(Stream::Stdout) {
+                AppSettings::ColoredHelp
+            } else {
+                AppSettings::ColorNever // in case it run on terminal without color support
+            });
         if !c.subcommands.is_empty() {
             subcmd = build_subcommands(subcmd, &c.subcommands);
             // If this parent command has no script source, require a subcommand.