feat(sysctl): add -a flag for printing the parameters

systeroid-core/src/sysctl.rs

@@ -2,6 +2,7 @@ use crate::error::Result;
 use crate::parsers::parse_kernel_docs;
 use rayon::prelude::*;
 use std::fmt::{self, Display, Formatter};
+use std::io::Write;
 use std::path::Path;
 use std::result::Result as StdResult;
 use sysctl::{CtlFlags, CtlIter, Sysctl as SysctlImpl};
@@ -143,4 +144,12 @@ impl Sysctl {
             });
         Ok(())
     }
+
+    /// Prints the available kernel parameters to the given output.
+    pub fn print_all<W: Write>(&self, output: &mut W) -> Result<()> {
+        for parameter in &self.parameters {
+            writeln!(output, "{} = {}", parameter.name, parameter.value)?;
+        }
+        Ok(())
+    }
 }

systeroid/src/args.rs

@@ -40,7 +40,7 @@ impl Args {
             .map_err(|e| eprintln!("error: {}", e))
             .ok()?;
 
-        if matches.opt_present("h") {
+        if matches.opt_present("h") || !matches.opt_present("a") {
             let usage = opts.usage_with_format(|opts| {
                 HELP_MESSAGE
                     .replace("{bin}", env!("CARGO_PKG_NAME"))

systeroid/src/lib.rs

@@ -6,26 +6,21 @@
 pub mod args;
 
 use crate::args::Args;
+use std::io;
 use systeroid_core::error::Result;
 use systeroid_core::sysctl::Sysctl;
 
 /// Runs `systeroid`.
 pub fn run(args: Args) -> Result<()> {
+    let mut stdout = io::stdout();
     let mut sysctl = Sysctl::init()?;
 
     if let Some(kernel_docs) = args.kernel_docs {
         sysctl.update_docs(&kernel_docs)?;
     }
 
-    for param in sysctl.parameters {
-        println!(
-            "{}\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n{}\n(from: {:?})\n",
-            param.name,
-            param
-                .description
-                .unwrap_or_else(|| String::from("no documentation")),
-            param.document.map(|d| d.path).unwrap_or_default(),
-        );
+    if args.all {
+        sysctl.print_all(&mut stdout)?;
     }
 
     Ok(())