shell script part 2

Answer is zero (0). Shell simple compared two number and returned result as true or false. Is 5 is less than 2? No. So 0 is returned. The Boolean (logical data) type is a primitive data type having one of two values

• True
• False

In shell:

• 0 value indicates false.
• 1 or non-zero value indicate true.

Examples

Operator	Example	Description	True / False	Evaluates To
5 > 12	echo $(( 5 > 12 ))	Is 5 greater than 12?	No (false)	0
5 == 10	echo $(( 5 == 10 ))	Is 5 equal to 10?	No (false)	0
5 != 2	echo $(( 5 != 2 ))	5 is not equal to 2?	Yes (true)	1
1 < 2	echo $(( 1 < 2 ))	Is 1 less than 2?	Yes (true)	1
5 == 5	echo $(( 5 == 5 ))	Is 5 equal to 5?	Yes (true)	1

Now, it makes no sense to use echo command for comparisons. But, when you compare it with some value it becomes very useful.

test command syntax

test condition && true-command || false-command

Type the following command at a shell prompt (is 5 greater than 2? ):

test 5 -gt 2 && echo "Yes" or  test 1 -lt 2 && echo "Yes"

echo Options

Options	Description
-n	do not print the trailing newline.
-e	enable interpretation of backslash escapes.
\b	backspace
\\	backslash
\n	new line
\r	carriage return
\t	horizontal tab
\v	vertical tab