From fb443270b14ad4d404f6b401f83b323a9769e667 Mon Sep 17 00:00:00 2001
From: Jonas Maier <>
Date: Tue, 10 Mar 2026 17:03:16 +0100
Subject: command-name completion based on PATH

---
 src/completion.rs | 34 +++++++++++++++++++++++++++++++++-
 src/main.rs       |  5 +++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/completion.rs b/src/completion.rs
index 2137b6f..d10aabd 100644
--- a/src/completion.rs
+++ b/src/completion.rs
@@ -1,4 +1,5 @@
 use crate::*;
+use std::path::{Path, PathBuf};
 use std::{env, fs};
 
 pub struct Suggestion {
@@ -80,10 +81,41 @@ pub fn variable_completion(session: Arc<Mutex<Session>>, prefix: BString) -> Vec
     out
 }
 
+#[derive(Default)]
+pub struct PathCache {
+    binaries: HashMap<BString, PathBuf>,
+}
+
+fn is_executable(path: &Path) -> bool {
+    use std::os::unix::fs::PermissionsExt;
+    fs::metadata(path)
+        .map(|m| m.permissions().mode() & 0o111 != 0)
+        .unwrap_or(false)
+}
+
+pub fn populate_path_cache(session: Arc<Mutex<Session>>) {
+    let path_var = env::var_os("PATH").unwrap();
+
+    let mut binaries = HashMap::new();
+
+    for dir in env::split_paths(&path_var) {
+        if let Ok(entries) = fs::read_dir(&dir) {
+            for entry in entries.flatten() {
+                let path = entry.path();
+                if path.is_file() && is_executable(&path) {
+                    binaries.insert(path.file_name().unwrap().as_bytes().to_vec(), path);
+                }
+            }
+        }
+    }
+
+    session.lock().unwrap().path_cache = PathCache { binaries };
+}
+
 pub fn command_completion(session: Arc<Mutex<Session>>, prefix: BString) -> Vec<Suggestion> {
     let se = session.lock().unwrap();
     let mut out = Vec::new();
-    for fun in se.funs.keys().chain(se.builtins.keys()) {
+    for fun in se.funs.keys().chain(se.builtins.keys()).chain(se.path_cache.binaries.keys()) {
         if fun.starts_with(&prefix) {
             out.push(Suggestion {
                 display: fun.to_vec(),
diff --git a/src/main.rs b/src/main.rs
index 5e7d40a..7a8d864 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -30,6 +30,7 @@ pub mod serialization;
 use linebuf::LineBuf;
 use raw::*;
 
+use crate::completion::PathCache;
 use crate::cursor::{Direction, move_cursor};
 use crate::history::HistoryEntry;
 use crate::parse::{Ast, PreExpansion};
@@ -74,6 +75,7 @@ pub struct Session {
     vars: HashMap<BString, BString>,
     funs: HashMap<BString, Ast<PreExpansion>>,
     socket_running: Option<export_fun::SocketRunning>,
+    path_cache: PathCache,
 
     /// n before end of history.len()
     /// 0 == not checking history
@@ -270,11 +272,14 @@ fn event_loop() {
         socket_running: None,
         vars: HashMap::new(),
         funs: HashMap::new(),
+        path_cache: Default::default(),
     };
 
     print!("{}", se.prompt());
 
     let session = Arc::new(Mutex::new(se));
+    completion::populate_path_cache(session.clone());
+
     let _sock_dropper = export_fun::listen(session.clone());
 
     loop {
-- 
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