Don't worry! It's only stuff...

String replace
sed -i 's|STRING_FROM|STRING_TO|g' FILE

add line to a file
sed -i '13i\YOUR_TEXT' FILE

Extract RPM Archiv
rpm2cpio FILENAME | cpio -i --make-directories

Get file atime, mtime, ctime
stat FILE

Change mtime from a file
touch -d "2005-05-05 15:55:55" FILE

Create selfextract archive under Linux
makeself.sh [-bzip2] DIR archiv.run "DESCRIPTION" COMMAND

Create Linux software RAID
mdadm --create /dev/md2 --level=raid5 --raid-devices=4 --spare-devices=0 /dev/sdb4
/dev/sdc4 /dev/sdd4

Wake On Lan (WOL)
wakeonlan 00:11:22:33:44:55

Change root and start bash
chroot /mnt /bin/bash

Enable / Disable swap
swapoff -a
swapon -a

extract initrd.gz
gunzip [geshifilter- ../initrd.gz | cpio -i --make-directories