Add --config-file option

src/clap_app.rs

@@ -265,6 +265,14 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
                 .hidden(true)
                 .help("Do not use the configuration file"),
         )
+        .arg(
+            Arg::with_name("config-file")
+                .long("config-file")
+                .conflicts_with("list-languages")
+                .conflicts_with("list-themes")
+                .hidden(true)
+                .help("Show path to the configuration file"),
+        )
         .subcommand(
             SubCommand::with_name("cache")
                 .about("Modify the syntax-definition and theme cache")

src/config.rs

@@ -1,16 +1,20 @@
 use std::env;
 use std::ffi::OsString;
 use std::fs;
+use std::path::PathBuf;
 
 use shell_words;
 
 use dirs::PROJECT_DIRS;
 use util::transpose;
 
+pub fn config_file() -> PathBuf {
+    PROJECT_DIRS.config_dir().join("config")
+}
+
 pub fn get_args_from_config_file() -> Result<Vec<OsString>, shell_words::ParseError> {
-    let config_file = PROJECT_DIRS.config_dir().join("config");
     Ok(transpose(
-        fs::read_to_string(config_file)
+        fs::read_to_string(config_file())
             .ok()
             .map(|content| get_args_from_str(&content)),
     )?

src/main.rs

@@ -50,6 +50,7 @@ use ansi_term::Style;
 
 use app::{App, Config};
 use assets::{clear_assets, config_dir, HighlightingAssets};
+use config::config_file;
 use controller::Controller;
 use inputfile::InputFile;
 use style::{OutputComponent, OutputComponents};
@@ -224,6 +225,10 @@ fn run() -> Result<bool> {
             } else if app.matches.is_present("list-themes") {
                 list_themes(&config)?;
 
+                Ok(true)
+            } else if app.matches.is_present("config-file") {
+                println!("{}", config_file().to_string_lossy());
+
                 Ok(true)
             } else {
                 run_controller(&config)