df -h show list of partitions mounted

ls -lSr |more show size of the files and directories ordered by size

du -sh dir1 estimate space used by directory 'dir1'

du -sh * | sort -rn show size of the files and directories sorted by size

rpm -q -a --qf '%10{SIZE}\t%{NAME}\n' | sort -k1,1n show space used by rpm packages installed sorted by size (fedora, redhat and like)

dpkg-query -W -f='${Installed-Size;10}\t${Package}\n' | sort -k1,1n show space used by deb packages installed sorted by size (ubuntu, debian and like)