Add basic touch command implementation

Author: morr0ne

docs/touch.txt

@@ -0,0 +1,29 @@
+use std::io::stdout;
+
+use puppyutils::{Result, cli};
+use xenia::{AtFlags, ClockId, Timestamps, clock_gettime, stdio::cwd, utimensat};
+
+pub fn main() -> Result {
+    let mut stdout = stdout();
+    let mut files = Vec::new();
+
+    cli! {
+        "touch", stdout, #error
+        Value(value) => {
+            files.push(value.into_owned());
+        }
+    };
+
+    let now = clock_gettime(ClockId::Realtime)?;
+
+    let timestamps = Timestamps {
+        last_access: now,
+        last_modification: now,
+    };
+
+    for file in files {
+        utimensat(cwd(), file, &timestamps, AtFlags::empty())?
+    }
+
+    Ok(())
+}

src/bin/touch.rs

@@ -9,6 +9,7 @@ pub mod bin {
     pub mod ls;
     pub mod mkdir;
     pub mod pwd;
+    pub mod touch;
     pub mod r#true;
     pub mod tty;
     pub mod uname;
@@ -33,6 +34,7 @@ fn main() -> Result {
         b"ls" => bin::ls::main(),
         b"mkdir" => bin::mkdir::main(),
         b"pwd" => bin::pwd::main(),
+        b"touch" => bin::touch::main(),
         b"true" => bin::r#true::main(),
         b"tty" => bin::tty::main(),
         b"uname" => bin::uname::main(),