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# Unix - Shell Relational Operators Example

Here is an example which uses all the relational operatos:

    #!/bin/sh

    a=10
    b=20

    if [ $a -eq $b ]
    then
       echo "$a -eq $b : a is equal to b"
    else
       echo "$a -eq $b: a is not equal to b"
    fi

    if [ $a -ne $b ]
    then
       echo "$a -ne $b: a is not equal to b"
    else
       echo "$a -ne $b : a is equal to b"
    fi

    if [ $a -gt $b ]
    then
       echo "$a -gt $b: a is greater than b"
    else
       echo "$a -gt $b: a is not greater than b"
    fi

    if [ $a -lt $b ]
    then
       echo "$a -lt $b: a is less than b"
    else
       echo "$a -lt $b: a is not less than b"
    fi

    if [ $a -ge $b ]
    then
       echo "$a -ge $b: a is greater or  equal to b"
    else
       echo "$a -ge $b: a is not greater or equal to b"
    fi

    if [ $a -le $b ]
    then
       echo "$a -le $b: a is less or  equal to b"
    else
       echo "$a -le $b: a is not less or equal to b"
    fi

This would produce following result:

    10 -eq 20: a is not equal to b
    10 -ne 20: a is not equal to b
    10 -gt 20: a is not greater than b
    10 -lt 20: a is less than b
    10 -ge 20: a is not greater or equal to b
    10 -le 20: a is less or  equal to b

There are following points to note down:

- There must be spaces between operators and expressions for example 2+2 is not correct, where as it should be written as 2 + 2.

- if...then...else...fi statement is a decision making statement which has been explained in next chapter.

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