Ubuntu Unleashed 2019 Edition: Covering 18.04, 18.10, 19.04

string1 not equal   to  string2

string2 not equal   to  string1

string1 is  not empty

string2 has a   length  greater than    zero

string1 has a   length  greater than    zero

If two strings are not equal in size, the system pads out the shorter string with
trailing spaces for comparison. That is, if the value of string1 is “abc”
and that of string2 is “ab”, string2 is padded with a trailing space for
comparison purposes; it has the value “ab “ (with a space after the letters).

Numeric Comparison

The following operators can be used to compare two numbers:

-eq—Compares    whether two numbers are equal

-ge—Compares    whether one number  is  greater than    or  equal   to  the other

number

-le—Compares    whether one number  is  less    than    or  equal   to  the other

number

-ne—Compares    whether two numbers are not equal

-gt—Compares    whether one number  is  greater than    the other   number

-lt—Compares    whether one number  is  less    than    the other   number

The following shell program compares three numbers, number1, number2,
and number3:

Click here to view code image
#!/bin/sh
number1=5
number2=10
number3=5

if  [   $number1    -eq $number3    ];  then

            echo    "number1    is  equal   to  number3"

else

            echo    "number1    is  not equal   to  number3"

fi

if  [   $number1    -ne $number2    ];  then

            echo    "number1    is  not equal   to  number2"

else

            echo    "number1    is  equal   to  number2"

fi