Find text within files:

grep "text" *.txt

Find a file by size:

find / -type f -size +20000k -exec ls -lh {} \; 2> /dev/null | awk '{ print $NF ": " $5 }'  | sort -nrk 2,2

See recent device changes:

dmesg

Remove all .svn files recursively:

find ./ -name ".svn" | xargs rm -Rf

Change already mounted read-only FS system to write:

mount -uw /

dd if=file.bin of=/dev/sda2

Display progress (1)

dd if=file.bin | cpipe -vr -vw -vt | dd of=/dev/sda2

Display progress (2)

dd if=file.bin | pv | dd of=/dev/sda2

tar -u -f user@server:file.tar --rsh-command=/usr/bin/ssh --rmt-command=/usr/sbin/rmt /root/backup/sql /etc/ /var/log/

On the master:
udp-sender --file /dev/sda

On the clients:
udp-receiver --file /dev/sda

nc -l -p 9000 | pv | dd of=/dev/sda

# On Slave, run
nc -l -p 9000 | dd of=/dev/sda

# On Master, run
dd if=/dev/sda | nc 192.168.1.220 9000