df

Overview

The df (disk free) command reports file system disk space usage. It shows the amount of disk space used and available on all mounted file systems.

Syntax

df [options] [file...]

Common Options

Option Description
-h Human readable sizes
-i List inode information
-T Print file system type
-a Show all file systems
-l Local file systems only
-t type Include specific types
-x type Exclude specific types
-P POSIX output format
--total Show total usage

Key Use Cases

  1. Disk space monitoring
  2. Storage management
  3. Capacity planning
  4. System maintenance
  5. Troubleshooting

Examples with Explanations

Example 1: Basic Usage

df -h

Show human-readable disk usage

Example 2: Inode Usage

df -i

Display inode information

Example 3: Specific Type

df -t ext4

Show only ext4 filesystems

Understanding Output

Columns explained: - Filesystem: Device/partition - Size: Total size - Used: Used space - Avail: Available space - Use%: Usage percentage - Mounted on: Mount point

Common Usage Patterns

  1. Check space usage:

    df -h /

  2. Monitor inodes:

    df -i /var

  3. Show file system types:

    df -T

Performance Analysis

  • Fast execution
  • Minimal system impact
  • Real-time information
  • Network fs impact
  • Cache utilization

Additional Resources

Monitoring Tips

  1. Regular space checks
  2. Inode monitoring
  3. Alert thresholds
  4. Trend analysis
  5. Capacity planning

Best Practices

  1. Use human readable format
  2. Check both space and inodes
  3. Monitor critical filesystems
  4. Document thresholds
  5. Regular maintenance