How to Use the ‘glances’ Command in Linux

The glances command in Linux provides a comprehensive overview of system performance. Acting as a real-time monitoring system, it offers insights into CPU, memory, disk usage, and more, all in an easy-to-read interface. Similar to commands like top and htop, glances takes system monitoring a step further by displaying additional information and allowing for more customization.

Whether you’re a system admin or web developer, the glances command can be an essential part of your toolkit. It’s particularly handy for those who need to keep an eye on system resources, troubleshoot performance issues, or optimize system efficiency. Alongside tools like vmstat and iostat, glances can provide a more holistic view of your system’s health and performance.

How to Install the glances Command

glances is not typically included by default in most Linux distributions, so you will need to install it. Here’s how you can install and uninstall glances on various Linux systems:

For Ubuntu/Debian-based systems:

To install:

sudo apt-get update
sudo apt-get install glances

To uninstall:

sudo apt-get remove glances

For Fedora:

To install:

sudo dnf install glances

To uninstall:

sudo dnf remove glances

For CentOS/RHEL:

To install:

sudo yum install glances

To uninstall:

sudo yum remove glances

For macOS (using Homebrew):

To install:

brew install glances

To uninstall:

brew uninstall glances

How to Use glances

1. Monitor System Resources

Syntax: glances

Explanation: Displays a real-time overview of system resources.

Example: glances

Output:

CPU     5.6%  MEM    42.1%  SWAP    0.0%  LOAD    0.45  0.36  0.31 
NETWORK   rx   102Kb/s   tx   58Kb/s 
DISK I/O  read  0b/s     write 20Kb/s

This output shows the current CPU usage at 5.6%, memory usage at 42.1%, no swap usage, network and disk I/O rates, and system load averages.

2. Monitor System Resources with a Specific Refresh Interval

Syntax: glances -t <seconds>

Explanation: Refreshes the display at a specific interval in seconds.

Example: glances -t 5

Output:

CPU     3.2%  MEM    40.2%  SWAP    0.0%  LOAD    0.25  0.30  0.28

This output is similar to the basic command but refreshes every 5 seconds.

3. Monitor Specific Processes by Name

Syntax: glances -p <process_name>

Explanation: Filters the display to show only specific processes by name.

Example: glances -p firefox

Output:

PID  1234  USER  john  VIRT  2.3G  RES  200M  CPU  12%  MEM  5%  TIME+  2:03  NAME  firefox

This output shows details about the Firefox process, including PID, user, virtual and resident memory, CPU and memory usage, and total time.

4. Run Glances in Web Server Mode

Syntax: glances -w

Explanation: Runs glances in web server mode, allowing access via a web browser.

Example: glances -w

Output:

Glances Web User Interface started on http://0.0.0.0:61208/

This output indicates that glances is running as a web server, and the user interface can be accessed through the provided URL.

5. Monitor System Resources with a Specific Configuration File

Syntax: glances -C <path_to_config_file>

Explanation: Starts glances with a specific configuration file.

Example: glances -C /etc/glances/glances.conf

This command allows you to use a custom configuration file to modify the behavior and appearance of glances.

6. Export Statistics to a CSV File

Syntax: glances --export csv --output-file <file.csv>

Explanation: Exports the statistics to a CSV file.

Example: glances --export csv --output-file stats.csv

This command exports the monitored data to a CSV file named stats.csv, allowing for further analysis or record-keeping.

7. Monitor Disk I/O by Disk Name

Syntax: glances -d <disk_name>

Explanation: Monitors specific disk I/O by disk name.

Example: glances -d sda

Output:

DISK I/O  sda  read  100Kb/s  write  50Kb/s

This output shows the read and write speeds specifically for the sda disk.

8. Monitor with Docker Plugin

Syntax: glances --enable-plugin docker

Explanation: Monitors Docker containers using the Docker plugin.

Example: glances --enable-plugin docker

Output:

DOCKER  ID  12345678  NAME  my_container  CPU  5%  MEM  10%  STATUS  Up 3 hours

This output shows details about a specific Docker container, including its ID, name, CPU and memory usage, and status.

9. Display Network Cumulative Stats

Syntax: glances --enable-plugin ip

Explanation: Displays cumulative network stats using the IP plugin.

Example: glances --enable-plugin ip

Output:

NETWORK  eth0  rx  1.2GB  tx  800MB

This output shows the cumulative received rx and transmitted tx data for the eth0 network interface.

More Linux commands: