Add --completion <SHELL> to provide shell completions

CHANGELOG.md

@@ -11,6 +11,7 @@
 - Add or remove individual style components without replacing all styles #2929 (@eth-p)
 - Automatically choose theme based on the terminal's color scheme, see #2896 (@bash)
 - Add option `--binary=as-text` for printing binary content, see issue #2974 and PR #2976 (@einfachIrgendwer0815)
+- Make shell completions available via `--completion <shell>`, see issue #2057 and PR #3126 (@einfachIrgendwer0815)
 
 ## Bugfixes
 

README.md

@@ -465,6 +465,12 @@ cargo install --locked bat
 Note that additional files like the man page or shell completion
 files can not be installed in this way. They will be generated by `cargo` and should be available in the cargo target folder (under `build`).
 
+Shell completions are also available by running:
+```bash
+bat --completion <shell>
+# see --help for supported shells
+```
+
 ## Customization
 
 ### Highlighting theme

build/application.rs

@@ -63,5 +63,22 @@ pub fn gen_man_and_comp() -> anyhow::Result<()> {
         out_dir.join("assets/completions/bat.zsh"),
     )?;
 
+    println!(
+        "cargo:rustc-env=BAT_GENERATED_COMPLETION_BASH={}",
+        out_dir.join("assets/completions/bat.bash").display()
+    );
+    println!(
+        "cargo:rustc-env=BAT_GENERATED_COMPLETION_FISH={}",
+        out_dir.join("assets/completions/bat.fish").display()
+    );
+    println!(
+        "cargo:rustc-env=BAT_GENERATED_COMPLETION_PS1={}",
+        out_dir.join("assets/completions/_bat.ps1").display()
+    );
+    println!(
+        "cargo:rustc-env=BAT_GENERATED_COMPLETION_ZSH={}",
+        out_dir.join("assets/completions/bat.zsh").display()
+    );
+
     Ok(())
 }

doc/long-help.txt

@@ -202,6 +202,9 @@ Options:
           This option exists for POSIX-compliance reasons ('u' is for 'unbuffered'). The output is
           always unbuffered - this option is simply ignored.
 
+      --completion <SHELL>
+          Show shell completion for a certain shell. [possible values: bash, fish, zsh, ps1]
+
       --diagnostic
           Show diagnostic information for bug reports.
 

doc/short-help.txt

@@ -58,6 +58,8 @@ Options:
           Only print the lines from N to M.
   -L, --list-languages
           Display all supported languages.
+      --completion <SHELL>
+          Show shell completion for a certain shell. [possible values: bash, fish, zsh, ps1]
   -h, --help
           Print help (see more with '--help')
   -V, --version

src/bin/bat/clap_app.rs

@@ -564,6 +564,17 @@ pub fn build_app(interactive_output: bool) -> Command {
                 .help("Do not load custom assets"),
         );
 
+    #[cfg(feature = "application")]
+    {
+        app = app.arg(
+            Arg::new("completion")
+            .long("completion")
+            .value_name("SHELL")
+            .value_parser(["bash", "fish", "ps1", "zsh"])
+            .help("Show shell completion for a certain shell. [possible values: bash, fish, zsh, ps1]"),
+        );
+    }
+
     #[cfg(feature = "lessopen")]
     {
         app = app

src/bin/bat/completions.rs

@@ -0,0 +1,6 @@
+use std::env;
+
+pub const BASH_COMPLETION: &str = include_str!(env!("BAT_GENERATED_COMPLETION_BASH"));
+pub const FISH_COMPLETION: &str = include_str!(env!("BAT_GENERATED_COMPLETION_FISH"));
+pub const PS1_COMPLETION: &str = include_str!(env!("BAT_GENERATED_COMPLETION_PS1"));
+pub const ZSH_COMPLETION: &str = include_str!(env!("BAT_GENERATED_COMPLETION_ZSH"));

src/bin/bat/main.rs

@@ -3,6 +3,8 @@
 mod app;
 mod assets;
 mod clap_app;
+#[cfg(feature = "application")]
+mod completions;
 mod config;
 mod directories;
 mod input;
@@ -347,6 +349,18 @@ fn run() -> Result<bool> {
         return Ok(true);
     }
 
+    #[cfg(feature = "application")]
+    if let Some(shell) = app.matches.get_one::<String>("completion") {
+        match shell.as_str() {
+            "bash" => println!("{}", completions::BASH_COMPLETION),
+            "fish" => println!("{}", completions::FISH_COMPLETION),
+            "ps1" => println!("{}", completions::PS1_COMPLETION),
+            "zsh" => println!("{}", completions::ZSH_COMPLETION),
+            _ => unreachable!("No completion for shell '{}' available.", shell),
+        }
+        return Ok(true);
+    }
+
     match app.matches.subcommand() {
         Some(("cache", cache_matches)) => {
             // If there is a file named 'cache' in the current working directory,