---
title: pidof — Find the PID of a running program
date: 2026-10-20
time: 12:00
model: admin
category: programs
author_type: human
summary: Prints the process IDs of a running program by name.
tags: program, Service and process management, pidof
---

Prints the process IDs of a running program by name.

## Basic Information

| Command Name | pidof |
| --- | --- |
| One-line Introduction | Prints the process IDs of a running program by name. |
| Provided by | sysvinit-utils (installed by default) |
| Official Documentation | https://man7.org/linux/man-pages/man8/pidof.8.html |
| Supported Operating Systems | Linux |
| Installation Status | Installed by default (no separate installation needed) |
| Category | Linux service and process management (tags: Process and resource management (tags: process, PID, lookup)) |

## What is this command?

pidof maps an executable name to the process IDs currently running it.

With several matches it prints them space separated, which suits restart logic in scripts.

## What problems does it solve?

- Check for a leftover process before restarting a service.
- Verify whether a program accidentally runs twice.
- Branch on running state inside a script.
- Obtain the PID to signal quickly.
## Key features

### Lookup by name

Pass the executable name and it prints matching PIDs.

- **When to use**: When checking whether a program runs
- **What you get**: PID list or empty output
- **Limitations**: Matches by name, not by full path
### Script branching

Use its output or exit status to decide whether the program runs.

- **When to use**: When writing restart automation
- **What you get**: Immediate running/not-running answer
- **Limitations**: Multiple PIDs may need handling
### Single PID selection

The -s option prints only the first matching PID.

- **When to use**: When a single target is enough
- **What you get**: One PID
- **Limitations**: Extra instances stay invisible
## Installation and usage

### Check whether it is installed

```
pidof --help
```

pacman -S sysvinit-tools   # Arch (varies by distribution)

## Real-world examples

### Lookup

Show PIDs of nginx processes.

```
# Show PIDs of processes named nginx
pidof nginx
```

### Single PID

Print only the first PID.

```
# Print only the first match
pidof -s nginx
```

### In a script

Restart only when it is running.

```
# Restart only if it is currently running
pid=$(pidof nginx) && kill -HUP $pid
```

---
Source (HTML): https://games.aidebatehub.com/programs/linux/services/pidof.html
This file is an auto-generated Markdown twin of the DevHub document.