Merge pull request #3563 from NORMAL-EX/feat/quiet-empty

feat: add --quiet-empty flag to suppress output on empty input

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ## Features
 
+- Add `--quiet-empty` (`-E`) flag to suppress output when input is empty. Closes #1936, see #3563 (@NORMAL-EX)
 - Improve native man pages and command help syntax highlighting by stripping overstriking, see #3517 (@akirk)
 
 ## Bugfixes

assets/completions/_bat.ps1.in

@@ -186,6 +186,7 @@ Register-ArgumentCompleter -Native -CommandName '{{PROJECT_EXECUTABLE}}' -Script
             [CompletionResult]::new('--acknowledgements'      , 'acknowledgements'      , [CompletionResultType]::ParameterName, 'Show acknowledgements.')
             [CompletionResult]::new('--set-terminal-title'    , 'set-terminal-title'    , [CompletionResultType]::ParameterName, 'Sets terminal title to filenames when using a pager.')
             [CompletionResult]::new('--diagnostic'            , 'diagnostic'            , [CompletionResultType]::ParameterName, 'Show diagnostic information for bug reports.')
+            [CompletionResult]::new('--quiet-empty'           , 'quiet-empty'           , [CompletionResultType]::ParameterName, 'Do not produce any output when the input is empty.')
         #   [CompletionResult]::new('-h'                      , 'h'                     , [CompletionResultType]::ParameterName, 'Print this help message.')
             [CompletionResult]::new('--help'                  , 'help'                  , [CompletionResultType]::ParameterName, 'Print this help message.')
         #   [CompletionResult]::new('-V'                      , 'V'                     , [CompletionResultType]::ParameterName, 'Show version information.')

assets/completions/bat.bash.in

@@ -100,6 +100,7 @@ _bat() {
 	--lessopen | \
 	--no-paging | \
 	--diagnostic | \
+	--quiet-empty | \
 	--acknowledgements | \
 	-h | --help | \
 	-V | --version | \
@@ -227,6 +228,7 @@ _bat() {
 			--lessopen
 			--completion
 			--diagnostic
+			--quiet-empty
 			--acknowledgements
 			--set-terminal-title
 			--help

assets/completions/bat.fish.in

@@ -61,7 +61,7 @@ function __bat_no_excl_args
         -s V -l version \
         -l acknowledgements \
         -l config-dir -l config-file \
-        -l diagnostic \
+        -l diagnostic -l quiet-empty \
         -l list-languages -l list-themes
 end
 
@@ -159,6 +159,7 @@ complete -c $bat -l config-file -f -d "Display location of configuration file" -
 complete -c $bat -l decorations -x -a "$decorations_opts" -d "When to use --style decorations" -n __bat_no_excl_args
 
 complete -c $bat -l diagnostic -d "Print diagnostic info for bug reports" -n __fish_is_first_arg
+complete -c $bat -l quiet-empty -d "Do not produce any output when the input is empty" -n __fish_is_first_arg
 
 complete -c $bat -s d -l diff -d "Only show lines with Git changes" -n __bat_no_excl_args
 

assets/completions/bat.zsh.in

@@ -62,6 +62,7 @@ _{{PROJECT_EXECUTABLE}}_main() {
         --completion='[show shell completion for a certain shell]:shell:(bash fish zsh ps1)'
         --set-terminal-title'[sets terminal title to filenames when using a pager]'
         --diagnostic'[show diagnostic information for bug reports]'
+        --quiet-empty'[do not produce any output when the input is empty]'
         -P'[disable paging]'
         "--no-config[don't use the configuration file]"
         "--no-custom-assets[don't load custom assets]"

assets/manual/bat.1.in

@@ -282,6 +282,10 @@ Show bat's cache directory.
 .IP
 Show diagnostic information for bug reports.
 .HP
+\fB\-\-quiet\-empty\fR
+.IP
+Do not produce any output when the input is empty (e.g. an empty file or empty stdin). This is useful in scripts where silent behavior is preferred for empty input.
+.HP
 \fB\-\-acknowledgements\fR
 .IP
 Show acknowledgements.

doc/long-help.txt

@@ -212,6 +212,10 @@ Options:
       --diagnostic
           Show diagnostic information for bug reports.
 
+  -E, --quiet-empty
+          When this flag is set, bat will produce no output at all when the input is empty. This is
+          useful when piping commands that may produce empty output, like 'git diff'.
+
       --acknowledgements
           Show acknowledgements.
 

doc/short-help.txt

@@ -60,6 +60,8 @@ Options:
           Display all supported languages.
       --completion <SHELL>
           Show shell completion for a certain shell. [possible values: bash, fish, zsh, ps1]
+  -E, --quiet-empty
+          Produce no output when the input is empty.
   -h, --help
           Print help (see more with '--help')
   -V, --version

src/bin/bat/app.rs

@@ -461,6 +461,7 @@ impl App {
                 Some("auto") => StripAnsiMode::Auto,
                 _ => unreachable!("other values for --strip-ansi are not allowed"),
             },
+            quiet_empty: self.matches.get_flag("quiet-empty"),
             theme: theme(self.theme_options()).to_string(),
             visible_lines: match self.matches.try_contains_id("diff").unwrap_or_default()
                 && self.matches.get_flag("diff")

src/bin/bat/clap_app.rs

@@ -643,6 +643,18 @@ pub fn build_app(interactive_output: bool) -> Command {
                 .hide_short_help(true)
                 .help("Show diagnostic information for bug reports."),
         )
+        .arg(
+            Arg::new("quiet-empty")
+                .long("quiet-empty")
+                .short('E')
+                .action(ArgAction::SetTrue)
+                .help("Produce no output when the input is empty.")
+                .long_help(
+                    "When this flag is set, bat will produce no output at all when \
+                     the input is empty. This is useful when piping commands that may \
+                     produce empty output, like 'git diff'.",
+                ),
+        )
         .arg(
             Arg::new("acknowledgements")
                 .long("acknowledgements")

src/config.rs

@@ -107,6 +107,9 @@ pub struct Config<'a> {
 
     // Whether or not to strip ANSI escape codes from the input
     pub strip_ansi: StripAnsiMode,
+
+    /// Whether or not to produce no output when input is empty
+    pub quiet_empty: bool,
 }
 
 #[cfg(all(feature = "minimal-application", feature = "paging"))]

src/printer.rs

@@ -454,6 +454,11 @@ impl Printer for InteractivePrinter<'_> {
         input: &OpenedInput,
         add_header_padding: bool,
     ) -> Result<()> {
+        // If input is empty and quiet_empty is enabled, skip all output
+        if self.content_type.is_none() && self.config.quiet_empty {
+            return Ok(());
+        }
+
         if add_header_padding && self.config.style_components.rule() {
             self.print_horizontal_line_term(handle, self.colors.rule)?;
         }
@@ -556,6 +561,11 @@ impl Printer for InteractivePrinter<'_> {
     }
 
     fn print_footer(&mut self, handle: &mut OutputHandle, _input: &OpenedInput) -> Result<()> {
+        // If input is empty and quiet_empty is enabled, skip footer
+        if self.content_type.is_none() && self.config.quiet_empty {
+            return Ok(());
+        }
+
         if self.config.style_components.grid()
             && (self.content_type.is_some_and(|c| c.is_text())
                 || self.config.show_nonprintable

tests/integration_tests.rs

@@ -3654,3 +3654,33 @@ fn plain_with_sized_terminal_width() {
         .stdout("hello \nworld\n")
         .stderr("");
 }
+
+#[test]
+fn quiet_empty_suppresses_output_on_empty_stdin() {
+    bat()
+        .arg("--quiet-empty")
+        .write_stdin("")
+        .assert()
+        .success()
+        .stdout("");
+}
+
+#[test]
+fn quiet_empty_does_not_affect_non_empty_input() {
+    bat()
+        .arg("--quiet-empty")
+        .write_stdin("hello\n")
+        .assert()
+        .success()
+        .stdout("hello\n");
+}
+
+#[test]
+fn quiet_empty_suppresses_output_on_empty_file() {
+    bat()
+        .arg("--quiet-empty")
+        .arg("empty.txt")
+        .assert()
+        .success()
+        .stdout("");
+}