Disk Usage

Code

# Filesystem usage
df -h
df -hT
df -i                          # inode usage

# Directory sizes (human-readable, summarized)
du -sh /var/*
du -h --max-depth=1 /var | sort -h | tail -20

# Largest files
find / -type f -size +500M -exec ls -lh {} + 2>/dev/null

# Inodes per directory (find inode-hogging dirs)
for d in /*; do echo "$(find "$d" -xdev | wc -l) $d"; done | sort -n | tail

# Mount and unmount
mount /dev/sdb1 /mnt/data
umount /mnt/data

# LVM quick check
lvs && vgs && pvs

Explanation

df shows filesystem capacity and free space, while du walks directories to find size hogs. The sort -h pipe ranks directories by size, making cleanup quick. Inode exhaustion, not bytes, can also cause 'no space left on device', so check df -i when disks look empty but writes fail.

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