various linux shell commands

gistfile1.sh

# Directory size
du --max-depth=1 ./ | sort -n -r


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# full hard disk copy
dd if=/dev/hdx of=/dev/hdy
dd if=/dev/hdx of=/path/to/image
dd if=/dev/hdx | gzip > /path/to/image.gz

#Hdx could be hda, hdb etc. In the second example gzip is used to compress the image if it is really just a backup. 

#Restore Backup of hard disk copy
dd if=/path/to/image of=/dev/hdx

gzip -dc /path/to/image.gz | dd of=/dev/hdx 

#MBR backup
#In order to backup only the first few bytes containing the MBR and the partition table you can use dd as well.

dd if=/dev/hdx of=/path/to/image count=1 bs=512 

#MBR restore

dd if=/path/to/image of=/dev/hdx

#Add "count=1 bs=446" to exclude the partition table from being written to disk. You can manually restore the table.