df

Additional Notes

df reports disk space usage by filesystem. It helps answer: which mounted filesystem is full?

Use df for filesystem-level space and du for directory/file-level space. They solve related but different problems.

Syntax

df [options] [file-or-filesystem...]

Parameters

• options: Flags that change how df behaves.
• device: Disk, partition, volume, or filesystem path to inspect or modify.
• target: Mount point, file, or storage object used by the operation.

Common Options

• -h, --human-readable: Show sizes like 10G or 512M.
• -T, --print-type: Show filesystem type.
• -i, --inodes: Show inode usage instead of block usage.
• -a, --all: Include pseudo, duplicate, and inaccessible filesystems.
• -x TYPE: Exclude filesystem type.
• -t TYPE: Include only filesystem type.

Examples

df

Show disk usage for mounted filesystems.

df -h

Show disk usage in human-readable units.

df -h /

Show space for the filesystem containing /.

df -hT

Show space and filesystem types.

df -ih

Show inode usage. This helps when a disk has space but cannot create files.

df -h -x tmpfs

Hide tmpfs filesystems.

Reading Output

• Filesystem: Device or virtual filesystem.
• Size: Total size.
• Used: Used space.
• Avail: Available space.
• Use%: Percent used.
• Mounted on: Mount point in the Linux directory tree.

Practical Notes

• If Use% is near 100%, find large directories with du.
• If inode usage is 100%, many small files may be the problem.
• df follows mounted filesystems, not just physical disks.
• Snap, Docker, virtual filesystems, and temporary filesystems can make output noisy.