feat(app): support different display types for parameters

systeroid-core/src/config.rs

@@ -1,3 +1,4 @@
+use crate::display::DisplayType;
 use crate::sysctl::Section;
 use colored::Color;
 use std::collections::HashMap;
@@ -14,10 +15,10 @@ macro_rules! map {
 /// General configuration.
 #[derive(Debug, Default)]
 pub struct Config {
+    /// Application configuration.
+    pub app: AppConfig,
     /// Sysctl configuration.
     pub sysctl: SysctlConfig,
-    /// Application configuration.
-    pub color: AppConfig,
 }
 
 /// Sysctl configuration.
@@ -36,6 +37,8 @@ pub struct AppConfig {
     pub section_colors: HashMap<Section, Color>,
     /// Default color for the output
     pub default_color: Color,
+    /// Display type of the kernel parameters.
+    pub display_type: DisplayType,
 }
 
 impl Default for AppConfig {
@@ -53,6 +56,7 @@ impl Default for AppConfig {
                 Section::Unknown => Color::BrightBlack
             },
             default_color: Color::BrightBlack,
+            display_type: DisplayType::default(),
         }
     }
 }

systeroid-core/src/display.rs

@@ -0,0 +1,18 @@
+/// Possible ways of displaying the kernel variables.
+#[derive(Debug)]
+pub enum DisplayType {
+    /// Print the kernel variable name along with its value.
+    Default,
+    /// Print only the name of the variable.
+    Name,
+    /// Print only the value of the variable.
+    Value,
+    /// Print only the value of the variable without new line.
+    Binary,
+}
+
+impl Default for DisplayType {
+    fn default() -> Self {
+        Self::Default
+    }
+}

systeroid-core/src/lib.rs

@@ -16,3 +16,6 @@ pub mod parsers;
 
 /// Configuration.
 pub mod config;
+
+/// Display options.
+pub mod display;

systeroid-core/src/sysctl.rs

@@ -1,4 +1,5 @@
 use crate::config::{AppConfig, SysctlConfig};
+use crate::display::DisplayType;
 use crate::error::Result;
 use crate::parsers::parse_kernel_docs;
 use colored::*;
@@ -119,15 +120,41 @@ impl Parameter {
     /// Prints the kernel parameter to given output.
     pub fn display_value<W: Write>(&self, config: &AppConfig, output: &mut W) -> Result<()> {
         if !config.no_color {
-            writeln!(
-                output,
-                "{} {} {}",
-                self.colored_name(config),
-                "=".color(config.default_color),
-                self.value.bold(),
-            )?;
+            match config.display_type {
+                DisplayType::Name => {
+                    writeln!(output, "{}", self.colored_name(config))?;
+                }
+                DisplayType::Value => {
+                    writeln!(output, "{}", self.value.bold())?;
+                }
+                DisplayType::Binary => {
+                    write!(output, "{}", self.value.bold())?;
+                }
+                DisplayType::Default => {
+                    writeln!(
+                        output,
+                        "{} {} {}",
+                        self.colored_name(config),
+                        "=".color(config.default_color),
+                        self.value.bold(),
+                    )?;
+                }
+            }
         } else {
-            writeln!(output, "{} = {}", self.name, self.value)?;
+            match config.display_type {
+                DisplayType::Name => {
+                    writeln!(output, "{}", self.name)?;
+                }
+                DisplayType::Value => {
+                    writeln!(output, "{}", self.value)?;
+                }
+                DisplayType::Binary => {
+                    write!(output, "{}", self.value)?;
+                }
+                DisplayType::Default => {
+                    writeln!(output, "{} = {}", self.name, self.value)?;
+                }
+            }
         }
         Ok(())
     }

systeroid/src/args.rs

@@ -1,6 +1,7 @@
 use getopts::Options;
 use std::env;
 use std::path::PathBuf;
+use systeroid_core::display::DisplayType;
 
 /// Help message for the arguments.
 const HELP_MESSAGE: &str = r#"
@@ -17,6 +18,8 @@ For more details see {bin}(8)."#;
 pub struct Args {
     /// Path of the Linux kernel documentation.
     pub kernel_docs: PathBuf,
+    /// Display type of the variables.
+    pub display_type: DisplayType,
     /// Whether if the unknown variable errors should be ignored.
     pub ignore_errors: bool,
     /// Parameter to explain.
@@ -29,12 +32,13 @@ impl Args {
     /// Parses the command-line arguments.
     pub fn parse() -> Option<Self> {
         let mut opts = Options::new();
-        opts.optflag("h", "help", "display this help and exit");
-        opts.optflag("V", "version", "output version information and exit");
         opts.optflag("a", "all", "display all variables");
         opts.optflag("A", "", "alias of -a");
         opts.optflag("X", "", "alias of -a");
+        opts.optflag("b", "binary", "print value without new line");
         opts.optflag("e", "ignore", "ignore unknown variables errors");
+        opts.optflag("N", "names", "print variable names without values");
+        opts.optflag("n", "values", "print only values of the given variable(s)");
         opts.optopt(
             "",
             "explain",
@@ -47,6 +51,8 @@ impl Args {
             "set the path of the kernel documentation\n(default: /usr/share/doc/linux/)",
             "<path>",
         );
+        opts.optflag("h", "help", "display this help and exit");
+        opts.optflag("V", "version", "output version information and exit");
 
         let matches = opts
             .parse(&env::args().collect::<Vec<String>>()[1..])
@@ -71,12 +77,22 @@ impl Args {
             println!("{} {}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"));
             None
         } else {
+            let display_type = if matches.opt_present("N") {
+                DisplayType::Name
+            } else if matches.opt_present("n") {
+                DisplayType::Value
+            } else if matches.opt_present("b") {
+                DisplayType::Binary
+            } else {
+                DisplayType::Default
+            };
             Some(Args {
                 kernel_docs: PathBuf::from(
                     matches
                         .opt_str("d")
                         .unwrap_or_else(|| String::from("/usr/share/doc/linux/")),
                 ),
+                display_type,
                 ignore_errors: matches.opt_present("e"),
                 param_to_explain: matches.opt_str("explain"),
                 param_names: matches.free,

systeroid/src/lib.rs

@@ -18,9 +18,10 @@ use systeroid_core::sysctl::Sysctl;
 pub fn run(args: Args) -> Result<()> {
     let mut config = Config::default();
     config.sysctl.ignore_errors = args.ignore_errors;
-    config.color.no_color = env::var("NO_COLOR").is_ok();
+    config.app.display_type = args.display_type;
+    config.app.no_color = env::var("NO_COLOR").is_ok();
     let mut sysctl = Sysctl::init(config.sysctl)?;
-    let mut app = App::new(&mut sysctl, &config.color);
+    let mut app = App::new(&mut sysctl, &config.app);
 
     if let Some(param) = args.param_to_explain {
         app.display_documentation(&param, &args.kernel_docs)?;