df -h Explained¶
Introduction¶
This article explains a common df usage that administrators and learners often need to understand clearly.
What This Command Means¶
The command performs this specific task with df:
df -h
Breaking Down the Command¶
dfis the command being run.- The options or arguments decide the behavior.
- The final value is the target, such as a file, process, service, package, host, URL, or directory.
Practical Examples¶
df -h
df -h
findmnt /var
Example output:
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 50G 18G 33G 36% /
When to Use It¶
Use df when you need to know whether a filesystem is full or how much capacity remains on a mounted filesystem.
Common Mistakes¶
- Confusing filesystem usage from df with directory size from du.
- Ignoring inode exhaustion when block space is still available.
- Checking the wrong mount point after bind mounts or separate filesystems.
Safer Alternatives¶
Inspect before changing state when possible:
findmnt /var
For wider changes, test on a small target before using the command broadly.
Related Guides¶
Summary¶
Understanding df -h is about knowing what each part does and checking the final state after running it.