Programming language commands for bash. Files with the .sh extension are bash scripts.

For Loop

One liner:

for i in {1..9}; do echo ${i}; done

Multiple Lines:

for i in {1..9}
do
    echo ${i}
done

Different ranges:

• Numeric Range:

  for i in {1..9}; do echo ${i}; done

• For Each:

  for i in apple banana cherry; do echo ${i}; done

• Command:

  for i in $(<Command>); do echo ${i}; done

• Array:

  ARR=('apple' 'banana' 'cherry')
  for i in "${ARR[@]}"; do echo ${i}; done

Break and continue work as expected.

While Loop

Works in the same fashion as a for-loop, however, the loop continues until the control expression is false.

For example, this command prints every line in a file:

while read line;
do
    echo "$line"
done < file.txt