To find top 10 files eating up disk space
du -kh |sort -nr |head -10
To find disk space per folder/file in current directory.
du -sch .[!.]* * |sort -h
To find deleted files still being accessed by any processes
df looks fine, yet no files can be added, check inodes.
Number of inodes used can be high, if you've several small files.
df -h output goes to next multiple lines and you need some awk filters on positions,
df -P. It'll print one liners.
Other lesser used:
-- du —max-depth=1 -h /