Check How Long a Process Has Been Running on Ubuntu with ps

Overview

This guide explains how to determine the runtime of a process on an Ubuntu (or any Linux) system using the ps command. It covers two formatting options— etime (human‑readable) and etimes (seconds)—and shows how to hide the column header.

Step 1: Locate the Process ID (PID)

Identify the PID of the target process. For example, to find the PID of openvpn: pidof openvpn The command returns a numeric PID, e.g., 6176.

Step 2: Query the Process Runtime

Use ps with the -p flag to specify the PID and the -o flag to select the desired output column.

Human‑readable format (days‑hours‑minutes‑seconds): ps -p 6176 -o etime Raw seconds since start: ps -p 6176 -o etimes Both commands will output the elapsed time for the process with PID 6176.

Optional: Hide the Header Line

Append an equals sign to the format specifier to suppress the column header:

ps -p 6176 -o etime=

ps -p 6176 -o etimes=

Example Output

Running ps -p 6176 -o etime might produce: 15:25 Running ps -p 6176 -o etimes would show the same duration in seconds.

Extended Information

You can request additional fields such as PID, command line, user ID, and group ID: ps -p 6176 -o pid,cmd,etime,uid,gid Sample output:

PID CMD                                 ELAPSED UID   GID
6176 /usr/sbin/openvpn --daemon       15:25   65534 65534

This demonstrates how to replace the process name or PID with any other target you need to monitor.