feat(docs): support displaying multiple docs with extensible search

systeroid-core/src/sysctl/parameter.rs

@@ -127,7 +127,7 @@ impl Parameter {
     /// Prints the description of the kernel parameter to the given output.
     pub fn display_documentation<W: Write>(&self, output: &mut W) -> Result<()> {
         if let Some(documentation) = self.get_documentation() {
-            writeln!(output, "{}", documentation)?;
+            writeln!(output, "{}\n", documentation)?;
         } else {
             writeln!(output, "No documentation available")?;
         }

systeroid/src/app.rs

@@ -78,11 +78,11 @@ impl<'a> App<'a> {
     /// Displays the documentation of a parameter.
     pub fn display_documentation(&mut self, param_name: &str) -> Result<()> {
         let no_pager = self.sysctl.config.no_pager;
-        if let Some(parameter) = self.sysctl.get_parameter(param_name) {
+        for parameter in self.sysctl.get_parameters(param_name) {
             let mut fallback_to_default = false;
             if no_pager {
                 parameter.display_documentation(&mut self.stdout)?;
-                return Ok(());
+                continue;
             }
             let pager = env::var("PAGER").unwrap_or_else(|_| String::from("less"));
             match Command::new(&pager).stdin(Stdio::piped()).spawn() {

systeroid/src/args.rs

@@ -34,8 +34,8 @@ pub struct Args {
     pub preload_files: bool,
     /// Pattern for matching the parameters.
     pub pattern: Option<Regex>,
-    /// Parameter to explain.
-    pub param_to_explain: Option<String>,
+    /// Whether if the documentation should be shown.
+    pub explain_params: bool,
     /// Free string fragments.
     pub values: Vec<String>,
 }
@@ -61,11 +61,10 @@ impl Args {
         );
         opts.optflag("q", "quiet", "do not echo variable set");
         opts.optflag("d", "", "alias of -h");
-        opts.optopt(
+        opts.optflag(
             "E",
             "explain",
             "provide a detailed explanation for a variable",
-            "<var>",
         );
         opts.optopt(
             "d",
@@ -90,7 +89,7 @@ impl Args {
             || matches.opt_present("A")
             || matches.opt_present("X")
             || !matches.free.is_empty()
-            || matches.opt_str("explain").is_some()
+            || matches.opt_present("E")
             || preload_files;
 
         if show_help || env_args.len() == 1 {
@@ -142,7 +141,7 @@ impl Args {
                 pattern: matches
                     .opt_str("r")
                     .map(|v| Regex::new(&v).expect("invalid regex")),
-                param_to_explain: matches.opt_str("E"),
+                explain_params: matches.opt_present("E"),
                 values: matches.free,
             })
         }

systeroid/src/lib.rs

@@ -28,18 +28,20 @@ pub fn run(args: Args) -> Result<()> {
     let mut sysctl = Sysctl::init(config)?;
     let mut app = App::new(&mut sysctl)?;
 
-    if let Some(param) = args.param_to_explain {
-        app.update_documentation(args.kernel_docs.as_ref())?;
-        app.display_documentation(&param)?;
-    } else if args.values.is_empty() {
+    if args.values.is_empty() {
         app.display_parameters(args.pattern)?;
+    } else if args.explain_params {
+        app.update_documentation(args.kernel_docs.as_ref())?;
+        for param in args.values {
+            app.display_documentation(&param)?;
+        }
     } else if args.preload_files {
         for file in args.values {
             app.preload_values(file)?;
         }
     } else {
-        for param_name in args.values {
-            app.process_parameter(param_name, true)?;
+        for param in args.values {
+            app.process_parameter(param, true)?;
         }
     }