PIDOF(8)

🎀 PIDOF(8) 🎀

Okay bestie, this page is from the Linux System Administrator's Manual and it's all about pidof 💅

---

✨ NAME ✨

pidof - find the process ID of a running program 🔍

👀 SYNOPSIS ✨

pidof [-s] [-c] [-n] [-x] [-z] [-o omitpid[,omitpid...]] [-o
omitpid[,omitpid...]...] [-d sep] program [program...]

💖 DESCRIPTION ✨

So pidof finds the process IDs (PIDs) of the programs you name and prints those IDs to standard output 🖨️✨ It's giving "find me the PID, no cap."

Lowkey, on some systems this gets used in run-level change scripts, especially when the system has a System-V-style rc structure. In that case the scripts live in /etc/rc?.d, where ? is the runlevel 🧚 If your system has a start-stop-daemon(8) program, that's the one you should be using instead, periodt 💅

🎀 OPTIONS ✨

• -s — Single shot! 🎯 This tells the program to only return one PID, bestie.
• -c — Only return PIDs of processes running with the same root directory 🌸 This one gets ignored for non-root users, because they can't check the current root directory of processes they don't own 🙈
• -n — Skip the stat(2) system call on all binaries sitting on network-based file systems like NFS 🌐 Instead of using this flag, you can set and export the variable PIDOF_NETFS 🦋
• -q — Quiet mode 🤫 Don't show matched PIDs on standard out. The program just exits with a status of true or false to tell you whether a matching PID was found. Main character energy ✨
• -x — Scripts too! 📜 This makes the program also return the process IDs of shells that are running the named scripts 🐚
• -z — Tries to detect processes stuck in zombie (Z) status 🧟 Normally these get skipped, because messing with them can make pidof or related tools hang 💀 Quick tea: back in the day pidof would skip processes in the uninterruptible state (D) unless you passed -z. That's no longer the case! Now pidof finds and reports D state processes whether or not you use -z 🫶
• -d sep — Tells pidof to use sep as the output separator when more than one PID is shown 🍓 The default separator is a space.
• -o omitpid — Tells pidof to leave out processes with that process ID 🙅‍♀️ The special PID %PPID can be used to name the parent process of the pidof program, aka the calling shell or shell script 👑

📊 EXIT STATUS ✨

• 0 — Yay! At least one program with the requested name was found 🎉
• 1 — Oof, no program with the requested name was found 😭

📝 NOTES ✨

Okay so pidof is actually the same program as killall5(8). It just behaves based on the name it was called under 🧚

When you invoke pidof with the full pathname to the program you want, it's reasonably safe 🔒 Otherwise it's possible it returns PIDs of running programs that just happen to share the same name but are actually different programs. Iykyk 🙈 Also, the executable name of running processes is calculated with readlink(2), so symbolic links to executables will match too 🦋

Heads up, bestie! Zombie processes and processes in disk sleep (states Z and D, respectively) are ignored by default, because trying to access their stats can sometimes fail 💀 The -z flag tells pidof to try detecting these sleeping and zombie processes, but it comes with the risk of failing or hanging. Proceed with caution 🫣

🔗 SEE ALSO ✨

shutdown(8), init(8), halt(8), reboot(8), killall5(8) 💜

👑 AUTHOR ✨

Miquel van Smoorenburg 🧚

---

Okay that's the whole page, bestie 🌈 It's from sysvinit, last updated 01 Sep 1998. Love you, mwah 😘🦋💖