Shell

user
whoami

dd
dd if=#quellpfad# of=#zielpfad#

progress bar
see here

While
while #Ausdruck#; do #Kommando1#;#Kommando2#; done

Loop until success while [ -z $rc ] || [ $rc -ne 0 ]; do Command; rc=$?; sleep 10; done

for
for #var1# in #var2#; #Kommando1#;#Kommando2#; done

Define variables
user='Bob' helo='Good Morning $USER !' echo $helo Good Morning $USER ! user="Bob" helo="Good Morning $USER !" echo $helo Good Morning Bob !

http://www.chemie.fu-berlin.de/chemnet/general/topics/scripts_sh.html

Links:
useful comands