OmniBoot v1.5

Show files by size, biggest last
ls -lSr

List files only, no folders
ls -1Ap | grep -v /\$

Show top disk users in current dir.
du -s * | sort -k1,1rn | head

Sort paths by easy to interpret disk usage
du -hs /home/* | sort -k1,1h

Show free space on mounted filesystems
df -h

Show disks partitions sizes and types (run as root)
fdisk -l

Check file system (e2fsck)
-f force; -p automatic; -y yes for all; -v verbose
fsck.ext3 -vy /dev/sdX8

Tell superblocks (mke2fs, mkfs.ext2)
mkfs.ext3 -n /dev/sdX8

Check file system with specific superblock
fsck.ext3 -by xxspbxx /dev/sdX8

How long has this disk (system) been powered on in total
smartctl -A /dev/sda | grep Power_On_Hours

Show info about disk sda
hdparm -i /dev/sda

Test for unreadable blocks on disk sda
badblocks -s /dev/sda

convert from ext2 to ext3 (then edit fstab!)
tune2fs -j /dev/sdX2

resize filesystem
resize2fs ./initrd 16M

Clone HDD
dd if=/dev/sdX of=/dev/sdY

Compress HDD to Imagefile
dd if=/dev/sdX bs=1M | gzip > /folder/filename.gz

Expand Imagefile to HDD
gunzip -c /folder/filename.gz | dd of=/dev/hdX bs=1M

Create compressed partition image with partimage
partimage -z1 -f3 -codb save /dev/sdX2 /folder/filename

Mount iso
mount -t iso9660 -o loop filename.iso /folder