From a083035983bc2966fb9da0cdc34a96e564cdd0d2 Mon Sep 17 00:00:00 2001
From: Jay Hemnani <193022578+jayhemnani9910@users.noreply.github.com>
Date: Mon, 26 Oct 2026 01:17:56 +0530
Subject: [PATCH 1/2] pidof: accept %PPID in -o

procps-ng pidof takes the special value %PPID for the parent of pidof,
so a script can check whether another copy of it is running with
'pidof -o %PPID -x name'. It was rejected as an invalid PID.
---
 src/uu/pidof/src/pidof.rs   | 12 +++++++++++-
 tests/by-util/test_pidof.rs | 29 +++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/uu/pidof/src/pidof.rs b/src/uu/pidof/src/pidof.rs
index 00069481..e47563ff 100644
--- a/src/uu/pidof/src/pidof.rs
+++ b/src/uu/pidof/src/pidof.rs
@@ -185,7 +185,7 @@ pub fn uu_app() -> Command {
                 .help("Omit results with a given PID")
                 .value_delimiter(',')
                 .action(ArgAction::Append)
-                .value_parser(clap::value_parser!(usize))
+                .value_parser(parse_omit_pid)
                 .value_name("PID"),
         )
         .arg(
@@ -222,3 +222,13 @@ pub fn uu_app() -> Command {
                 .action(ArgAction::SetTrue),
         )
 }
+
+/// Parse an `-o` value: a PID, or `%PPID` for the parent of pidof (the
+/// calling shell or script).
+fn parse_omit_pid(value: &str) -> Result<usize, String> {
+    #[cfg(unix)]
+    if value == "%PPID" {
+        return Ok(std::os::unix::process::parent_id() as usize);
+    }
+    value.parse::<usize>().map_err(|e| e.to_string())
+}
diff --git a/tests/by-util/test_pidof.rs b/tests/by-util/test_pidof.rs
index 3dc7059d..8570693e 100644
--- a/tests/by-util/test_pidof.rs
+++ b/tests/by-util/test_pidof.rs
@@ -83,6 +83,35 @@ fn test_omit_pid() {
     }
 }
 
+#[test]
+#[cfg(target_os = "linux")]
+fn test_omit_pid_ppid() {
+    // pidof runs as a child of this test, so %PPID names this process.
+    let argv0 = std::env::args().next().unwrap();
+    let our_name = std::path::Path::new(argv0.as_str())
+        .file_name()
+        .unwrap()
+        .to_str()
+        .unwrap()
+        .to_owned();
+    let our_pid = std::process::id().to_string();
+
+    new_ucmd!()
+        .arg(&our_name)
+        .succeeds()
+        .stdout_contains(&our_pid);
+    let result = new_ucmd!().args(&["-o", "%PPID", &our_name]).run();
+    result.no_stderr();
+    assert!(
+        !result
+            .stdout_str()
+            .split_whitespace()
+            .any(|pid| pid == our_pid),
+        "{} contains {our_pid}",
+        result.stdout_str()
+    );
+}
+
 #[test]
 #[cfg(target_os = "linux")]
 fn test_separator() {

From 4f1424e1558a3fa7510b5fb2763dcd0b5b6e75d6 Mon Sep 17 00:00:00 2001
From: Jay Hemnani <193022578+jayhemnani9910@users.noreply.github.com>
Date: Tue, 27 Oct 2026 12:28:06 +0530
Subject: [PATCH 2/2] pidof: test %PPID in a list and find the test binary with
 current_exe

---
 tests/by-util/test_pidof.rs | 33 +++++++++++++++------------------
 1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/tests/by-util/test_pidof.rs b/tests/by-util/test_pidof.rs
index 8570693e..f48cc0b0 100644
--- a/tests/by-util/test_pidof.rs
+++ b/tests/by-util/test_pidof.rs
@@ -87,29 +87,26 @@ fn test_omit_pid() {
 #[cfg(target_os = "linux")]
 fn test_omit_pid_ppid() {
     // pidof runs as a child of this test, so %PPID names this process.
-    let argv0 = std::env::args().next().unwrap();
-    let our_name = std::path::Path::new(argv0.as_str())
-        .file_name()
-        .unwrap()
-        .to_str()
-        .unwrap()
-        .to_owned();
+    let exe = std::env::current_exe().unwrap();
+    let our_name = exe.file_name().unwrap().to_str().unwrap();
     let our_pid = std::process::id().to_string();
 
     new_ucmd!()
-        .arg(&our_name)
+        .arg(our_name)
         .succeeds()
         .stdout_contains(&our_pid);
-    let result = new_ucmd!().args(&["-o", "%PPID", &our_name]).run();
-    result.no_stderr();
-    assert!(
-        !result
-            .stdout_str()
-            .split_whitespace()
-            .any(|pid| pid == our_pid),
-        "{} contains {our_pid}",
-        result.stdout_str()
-    );
+    for omit in ["%PPID", "1,%PPID"] {
+        let result = new_ucmd!().args(&["-o", omit, our_name]).run();
+        result.no_stderr();
+        assert!(
+            !result
+                .stdout_str()
+                .split_whitespace()
+                .any(|pid| pid == our_pid),
+            "-o {omit}: {} contains {our_pid}",
+            result.stdout_str()
+        );
+    }
 }
 
 #[test]