How to get the start time of a long-running Linux process?

👋 Hey there tech enthusiasts! Welcome back to my tech blog! Today, we're going to dive into a common yet perplexing question: "How to get the start time of a long-running Linux process?"

Have you ever found yourself scratching your head, wondering how to find the exact start time of an old running process on Linux? 🤔 Trust me, you're not alone in this conundrum. Many Linux users face the frustration of not being able to retrieve accurate start time information for older processes.

So, let's tackle this issue head-on and explore some easy solutions! 💡

Firstly, the command we often turn to for process-related information is ps. However, as pointed out in the question, its default behavior might not provide the precise start time for long-running processes. It tends to display just the date if the process isn't from today and only the year if it isn't from this year. But fear not, the precision isn't lost forever!

To retrieve the start time of a long-running Linux process, we can turn to the /proc file system. 📁 This special file system provides an interface to kernel data structures and helps us gain insights into processes' attributes, including their start time.

To get started, simply open up your terminal and follow these steps:

1. Identify the process ID (PID) of the process for which you want to find the start time. You can use ps -e or ps aux to list all running processes and their respective PIDs.

2. Once you have the PID, navigate to the corresponding /proc directory using the command cd /proc/{PID}.

3. Now, to obtain the start time, you can simply use the ls command and check the timestamp of the starttime file. 📅 This file contains the time at which the process started, represented in clock ticks since the system boot time.

   ls -ld starttime

   The output will give you the exact start time of the process in the format: YYYY-MM-DD HH:MM:SS.

Congratulations! You've successfully retrieved the start time of the long-running Linux process! 🎉

Now, let's address a frequently asked question: "What if the /proc/{PID}/starttime file is not available?"

If you encounter this, it means that the process's information is no longer stored in the /proc directory. Sadly, there's no built-in way to retrieve the start time in such cases. However, fret not! There are alternative methods available, such as using external process monitoring tools like htop or even parsing log files, which may provide the desired information.

Remember, there's always a way in the Linux world! 🐧

Before I wrap up this guide, I want to encourage you to share your thoughts and any other solutions you might have. Let's build a vibrant community discussion below. 👇

So, what have your experiences been while trying to obtain the start time of a long-running Linux process? Have you discovered any additional tips or tricks? Share your findings in the comments section! Let's learn from each other and empower the tech community.

Until next time, stay curious, stay geeky! 💻✌️