Support BAT_WIDTH as an alias for --terminal-width

Signed-off-by: Asish Kumar <officialasishkumar@gmail.com>

src/bin/bat/clap_app.rs

@@ -240,6 +240,7 @@ pub fn build_app(interactive_output: bool) -> Command {
         .arg(
             Arg::new("terminal-width")
                 .long("terminal-width")
+                .overrides_with("terminal-width")
                 .value_name("width")
                 .hide_short_help(true)
                 .allow_hyphen_values(true)
@@ -255,10 +256,13 @@ pub fn build_app(interactive_output: bool) -> Command {
                             })
                             .map_err(|e| e.to_string())
                     })
-                .help(
+                .help("Explicitly set the width of the terminal instead of determining it automatically.")
+                .long_help(
                     "Explicitly set the width of the terminal instead of determining it \
                      automatically. If prefixed with '+' or '-', the value will be treated \
-                     as an offset to the actual terminal width. See also: '--wrap'.",
+                     as an offset to the actual terminal width. This can also be configured \
+                     via the BAT_WIDTH environment variable (e.g. export BAT_WIDTH=\"100\"). \
+                     See also: '--wrap'.",
                 ),
         )
         .arg(

src/bin/bat/config.rs

@@ -153,6 +153,7 @@ fn get_args_from_str(content: &str) -> Result<Vec<OsString>, shell_words::ParseE
 pub fn get_args_from_env_vars() -> Vec<OsString> {
     [
         ("--tabs", "BAT_TABS"),
+        ("--terminal-width", "BAT_WIDTH"),
         ("--theme", bat::theme::env::BAT_THEME),
         ("--theme-dark", bat::theme::env::BAT_THEME_DARK),
         ("--theme-light", bat::theme::env::BAT_THEME_LIGHT),

src/bin/bat/main.rs

@@ -328,6 +328,7 @@ fn invoke_bugreport(app: &App, cache_dir: &Path) {
             "BAT_STYLE",
             "BAT_TABS",
             "BAT_THEME",
+            "BAT_WIDTH",
             bat::theme::env::BAT_THEME_DARK,
             bat::theme::env::BAT_THEME_LIGHT,
             "COLORTERM",