Reading from a file

for line in $(cat /etc/passwd) do echo $line done

Iterate for a range

for number in {1..10} do echo “Current number is $number” done

Loop for values given

for planet in earth mars saturn jupiter do echo “The planet name is $planet” done

Loop for variable containing multiple values

planets=”earth mars […]

$? => Return code of previous command $0 => Name of the script itself $1-9 => Argument number 1 to 9 given to script ${10} => Argument number 10 given to script $# => Total number of arguments given to script $@ => All arguments given to script but as an individual string values “$*” […]