Which command would you use to check the size of a mounted filesystem after resizing?

• A. df -h
• B. ls -l
• C. cat /proc/mounts
• D. du -sh

Answer: (A)

When you resize a filesystem, you want to verify the new capacity of the mounted space. The right tool for this is df, which reports the size, used, and available space for each mounted filesystem. Using the human-readable option makes the numbers easy to interpret. For example, running df -h /mount/point will show a Size value that reflects the new, expanded capacity. This confirms the resize took effect. Other commands don’t provide the overall filesystem capacity: listing files doesn’t show total space; reading /proc/mounts shows what’s mounted but not sizes; and computing the size of a directory with du -sh reflects only that directory’s usage, not the entire filesystem.