监控系统资源：`df`、`du`、`free`

Keeping an eye on your system's resources is crucial for smooth operation. Just like a car needs fuel and oil, your computer needs enough disk space and memory to run efficiently.

Ignoring these can lead to slow performance, crashes, or even data loss.

The df command, short for "disk free", reports the amount of available disk space used by file systems.

It's your go-to command to see how much room is left on your partitions.

Let's try df with the -h option for human-readable output. This makes sizes like gigabytes (GB) and megabytes (MB) easy to understand.

Run this command in your terminal:

The output of df -h shows several columns:

• Filesystem: The name of the disk partition.
• Size: Total capacity of the partition.
• Used: Space currently occupied.
• Avail: Remaining free space.
• Use%: Percentage of disk space used.
• Mounted on: Where the filesystem is accessible in the directory tree.

While df shows overall disk free space, du ("disk usage") estimates file space usage, primarily for specific files or directories.

It helps you find out which folders are taking up the most space.

To see the total size of a directory in a human-readable format, use -s (summary) and -h (human-readable) with du. Replace /var/log with any directory you want to check.

Want to see the size of subdirectories within a folder? Use --max-depth=N to limit the depth of the output. Here, we'll see direct subdirectories (depth 1).

Memory (RAM) is vital for your system's speed. The free command displays the total amount of free and used physical and swap memory in the system.

Keeping an eye on free memory helps prevent slowdowns.

Similar to df, using the -h option with free provides output that's much easier to read. It shows memory in KB, MB, or GB.

You're running low on disk space and want to find which large directories are consuming it. Which command is best suited for this task?

Great job! In this lesson, you learned how to monitor your Linux system's vital resources:

• df: Check overall disk free space.
• du: Estimate disk usage for files and directories.
• free: Monitor physical and swap memory usage.

These commands are essential tools for maintaining a healthy and optimized system!