feat(cli): support explaining multiple parameters

README.md

@@ -385,10 +385,16 @@ systeroid -E user.max_user_namespaces --docs /usr/share/doc/linux
 
 To change the default pager (`less(1)`), you can use the `PAGER` environment variable. Also, you can simply use `--no-pager` flag to disable it.
 
-```
+```sh
 systeroid -E kernel.ctrl-alt-del --no-pager
 ```
 
+It is also possible to retrieve information about multiple parameters:
+
+```sh
+systeroid -E --pattern '.*ipv4.*' --no-pager
+```
+
 ## TUI
 
 ### Usage

systeroid-core/src/sysctl/parameter.rs

@@ -170,7 +170,7 @@ impl Parameter {
         if let Some(documentation) = self.get_documentation() {
             writeln!(output, "{}\n", documentation)?;
         } else {
-            writeln!(output, "No documentation available")?;
+            writeln!(output, "No documentation available for {}", self.name)?;
         }
         Ok(())
     }
@@ -267,7 +267,7 @@ mod tests {
         let mut output = Vec::new();
         parameter.display_documentation(&mut output)?;
         assert_eq!(
-            "No documentation available\n",
+            format!("No documentation available for {}\n", parameter.name),
             String::from_utf8_lossy(&output)
         );
 

systeroid/src/app.rs

@@ -68,6 +68,7 @@ impl<'a, Output: Write> App<'a, Output> {
         &mut self,
         pattern: Option<Regex>,
         display_deprecated: bool,
+        explain: bool,
     ) -> Result<()> {
         let parameters = self.sysctl.parameters.clone();
         let mut parameters = parameters.iter().filter(|parameter| {
@@ -81,7 +82,11 @@ impl<'a, Output: Write> App<'a, Output> {
             }
             true
         });
-        self.print_parameters(&mut parameters)
+        if explain {
+            parameters.try_for_each(|parameter| self.display_documentation(&parameter.name))
+        } else {
+            self.print_parameters(&mut parameters)
+        }
     }
 
     /// Displays the documentation of a parameter.
@@ -242,14 +247,14 @@ mod tests {
 
         let mut app = App::new(&mut sysctl, &mut output, OutputType::Default);
 
-        app.display_parameters(Regex::new("kernel|vm").ok(), false)?;
+        app.display_parameters(Regex::new("kernel|vm").ok(), false, false)?;
         let result = String::from_utf8_lossy(app.output);
         assert!(result.contains("vm.zone_reclaim_mode ="));
         assert!(result.contains("kernel.version ="));
         app.output.clear();
 
         app.output_type = OutputType::Tree;
-        app.display_parameters(None, true)?;
+        app.display_parameters(None, true, false)?;
         assert!(String::from_utf8_lossy(app.output).contains("─ osrelease ="));
         app.output.clear();
 

systeroid/src/lib.rs

@@ -37,7 +37,7 @@ pub fn run<Output: Write>(args: Args, output: &mut Output) -> Result<()> {
     if args.preload_system_files {
         app.preload_from_system()?;
     } else if args.values.is_empty() {
-        app.display_parameters(args.pattern, args.display_deprecated)?;
+        app.display_parameters(args.pattern, args.display_deprecated, args.explain)?;
     } else if args.explain {
         for param in args.values {
             app.display_documentation(&param)?;