Table of Contents

Bash programming

Conditional operators

operator produces true if... no. of operands
-n operand has non zero length 1
-z operand has zero length 1
-d there exists a directory whose name is operand 1
-f there exists a file whose name is operand 1
-eq the operands are integers and they are equal 2
-neq the opposite of -eq 2
= the operands are equal (as strings) 2
!= opposite of = 2
-lt operand1 is strictly less than operand2 (both operands should be integers) 2
-gt operand1 is strictly greater than operand2 (both operands should be integers) 2
-ge operand1 is greater than or equal to operand2 (both operands should be integers) 2
-le operand1 is less than or equal to operand2 (both operands should be integers) 2

See also Bash test and comparison functions

For loops

A loop over integers: 

for ((i=1;i<=10;i+=1)); do
echo $i
done

While loops

myvar=0
while [ $myvar -le 10 ]
do
    echo $myvar
    myvar=$(( $myvar + 1 ))
done

Links