Add `realpath` applet

README.md

@@ -44,6 +44,7 @@ code between applets, making for an overall smaller binary.
 - nproc
 - printenv
 - pwd
+- readlink
 - rev
 - rm
 - rmdir

src/cmd/mod.rs

@@ -35,6 +35,7 @@ mod nologin;
 mod nproc;
 mod printenv;
 mod pwd;
+mod realpath;
 mod rev;
 mod rm;
 mod rmdir;
@@ -92,6 +93,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
         "nproc" => Some(Box::new(nproc::Nproc::default())),
         "printenv" => Some(Box::new(printenv::Printenv::default())),
         "pwd" => Some(Box::new(pwd::Pwd::default())),
+        "realpath" => Some(Box::new(realpath::Realpath::default())),
         "rev" => Some(Box::new(rev::Rev::default())),
         "rm" => Some(Box::new(rm::Rm::default())),
         "rmdir" => Some(Box::new(rmdir::Rmdir::default())),
@@ -107,7 +109,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
     }
 }
 
-pub static COMMANDS: [&str; 38] = [
+pub static COMMANDS: [&str; 39] = [
     "base32",
     "base64",
     "basename",
@@ -135,6 +137,7 @@ pub static COMMANDS: [&str; 38] = [
     "nproc",
     "printenv",
     "pwd",
+    "realpath",
     "rev",
     "rm",
     "rmdir",

src/cmd/realpath/mod.rs

@@ -0,0 +1,66 @@
+use super::Cmd;
+use clap::{Arg, ArgAction, Command, ValueHint};
+use std::{env, fs, io, process};
+
+#[derive(Debug, Default)]
+pub struct Realpath;
+
+impl Cmd for Realpath {
+    fn cli(&self) -> clap::Command {
+        Command::new("realpath")
+            .about("return resolved physical path")
+            .author("Nathan Fisher")
+            .version(env!("CARGO_PKG_VERSION"))
+            .args([
+                Arg::new("quiet")
+                    .short('q')
+                    .long("quiet")
+                    .help("ignore warnings")
+                    .action(ArgAction::SetTrue),
+                Arg::new("path")
+                    .value_hint(ValueHint::AnyPath)
+                    .num_args(1..)
+                    .required(false),
+            ])
+    }
+
+    fn run(&self, matches: Option<&clap::ArgMatches>) -> Result<(), Box<dyn std::error::Error>> {
+        let Some(matches) = matches else {
+            return Err(io::Error::new(io::ErrorKind::Other, "no input").into());
+        };
+        if let Some(files) = matches.get_many::<String>("path") {
+            let mut erred = false;
+            for f in files {
+                match fs::canonicalize(f) {
+                    Ok(p) => println!("{}", p.display()),
+                    Err(e) => {
+                        if !matches.get_flag("quiet") {
+                            erred = true;
+                        } else {
+                            return Err(e.into());
+                        }
+                    }
+                }
+            }
+            if erred {
+                process::exit(1);
+            }
+        } else {
+            match env::current_dir().and_then(|d| fs::canonicalize(d)) {
+                Ok(p) => println!("{}", p.display()),
+                Err(e) => {
+                    if matches.get_flag("quiet") {
+                        process::exit(1);
+                    } else {
+                        return Err(e.into());
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+
+    fn path(&self) -> Option<crate::Path> {
+        Some(crate::Path::Bin)
+    }
+}