Shell Script to Monitor CPU and Memory Usage in Linux

Monitoring system resource utilization is crucial for ensuring optimal system performance and identifying potential issues. In this article, we will explore how to write a shell script that monitors CPU and memory usage of a specific process in Linux.

To monitor the status of a single process in batch mode, we can use the `top` command with options `-b`, `-d`, and `-p`. The `-b` option tells `top` to run in batch mode, while `-d` specifies the delay between updates. The `-p` option allows us to specify the process ID of the process we want to monitor.

For example, let's say we want to monitor the CPU usage of the `mpv` process every two seconds until it is manually terminated. We can use the following command:

```

$ top -b -d 2 -p $(pidof mpv)

```

This will keep updating the status of the `mpv` process every two seconds, displaying its CPU usage and other relevant information.

To monitor changes to a log file using the `tail` command, we can use the `-f` option. This option tells `tail` to follow the specified file and display new lines as they are added.

For example, let's say we want to write the CPU usage data of the `mpv` process to a log file named `/tmp/log_ps.txt`. We can use the following command:

```

$ tail -f /tmp/log_ps.txt

```

This will display the CPU usage data of the `mpv` process every two seconds, along with the current time and process name.

To automate this process, we can write a shell script that uses `top` and `tail` commands to monitor CPU usage of a specific process. Here's an example script:

```bash

#!/bin/bash

PNAME='mpv'

LOG_FILE='/tmp/log_ps.txt'

while true

CPU_USAGE=$(top -b -n 1 -p $(pidof $PNAME) | awk '{print $9}')

DATE=$(date)

echo '$DATE, $PNAME, $(pidof $PNAME), $CPU_USAGE' >> $LOG_FILE

sleep 2

done

```

This script uses the `top` command to get the CPU usage of the `mpv` process and writes it to a log file named `/tmp/log_ps.txt`. It also includes the current time, process name, and PID in the log entry. The `while true` loop ensures that the script runs indefinitely until it is manually terminated.

In conclusion, this shell script provides a simple way to monitor CPU usage of a specific process in Linux. By modifying the script to include memory usage monitoring, we can gain even more insight into system resource utilization.

Shell script to monitor cpu and memory usage in linux