From 0f19a43339b67676ede9c1a1b819c7ceab3dcaea Mon Sep 17 00:00:00 2001
From: Jesse Rosenstock <jmr@google.com>
Date: Tue, 28 Apr 2026 13:34:44 +0200
Subject: [PATCH] Add --list flag to multicall binary

Add a --list option that prints all registered utility names, one per
line. This matches the existing convention in uutils/coreutils and
enables scripts to dynamically discover available utilities without
hardcoding lists.

Update the usage text to document the new flag.
---
 src/bin/util-linux.rs | 10 +++++++++-
 tests/tests.rs        | 17 +++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/bin/util-linux.rs b/src/bin/util-linux.rs
index 6a942ee8..6974b880 100644
--- a/src/bin/util-linux.rs
+++ b/src/bin/util-linux.rs
@@ -21,7 +21,10 @@ include!(concat!(env!("OUT_DIR"), "/uutils_map.rs"));
 
 fn usage<T>(utils: &UtilityMap<T>, name: &str) {
     println!("{name} {VERSION} (multi-call binary)\n");
-    println!("Usage: {name} [function [arguments...]]\n");
+    println!("Usage: {name} [function [arguments...]]");
+    println!("       {name} --list\n");
+    println!("Options:");
+    println!("      --list    lists all defined functions, one per row\n");
     println!("Currently defined functions:\n");
     #[allow(clippy::map_clone)]
     let mut utils: Vec<&str> = utils.keys().map(|&s| s).collect();
@@ -123,6 +126,11 @@ fn main() {
                     }
                     usage(&utils, binary_as_util);
                     process::exit(0);
+                } else if util == "--list" {
+                    for util_name in utils.keys() {
+                        println!("{util_name}");
+                    }
+                    process::exit(0);
                 } else {
                     not_found(&util_os);
                 }
diff --git a/tests/tests.rs b/tests/tests.rs
index 8f94a09a..a1d8ccee 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -90,3 +90,20 @@ mod test_mcookie;
 #[cfg(feature = "uuidgen")]
 #[path = "by-util/test_uuidgen.rs"]
 mod test_uuidgen;
+
+#[test]
+fn test_list() {
+    let out = std::process::Command::new(TESTS_BINARY)
+        .arg("--list")
+        .output()
+        .unwrap();
+    assert!(out.status.success());
+    let stdout = String::from_utf8(out.stdout).unwrap();
+    let lines: Vec<&str> = stdout.lines().collect();
+    assert!(!lines.is_empty());
+    // Can be replaced with lines.is_sorted() starting with Rust 1.82.
+    assert!(lines.windows(2).all(|w| w[0] <= w[1]));
+    // Spot-check a few utilities that should always be present.
+    assert!(lines.contains(&"rev"));
+    assert!(lines.contains(&"dmesg"));
+}