**expr** command** **evaluates arguments as an expression.

We mostly use this command when we do the mathematical compputations . We have used expr command in our shell examples - you can see some scripts at - Practice Examples . Lets see some more options and examples of **expr** command as discussed below .

#### 1. Basic example -

Run the below expr command on your terminal .Returns **1** (true) if the expressions are equivalent, or **0** (false) if they are not .Here, the values **3** and **3** are equal, and therefore *equivalent*, so the output will be:

expr 3 = 3
Output - 1

#### 2. Evaluating string -

Run the below expr command on your terminal . Here, two strings are being compared for equivalence. If the strings match exactly, character-for-character, the result will be **1** (true). Otherwise, the result will be **0**. Here, the result is:

expr '3' = '3'
Output - 1

#### 3. Multiplication of two integers-

In mathematical computation shell doesn't multiple two numbers lik num = $x*$y , you have to use **expr** or **let** command to perfom any mathematical operatiosn . Lets run the following command to multiply two numbers .

expr 5 * 5
**Output -** 25

#### 4. Division of two integers-

Here we will use **/** as a division operator . But **/** has a special meaning in Linux / Unix shell script so we have to suppress its special meaning by providing escape charater** '\'** . So our expr command for division looks like -

expr 20 \/ 5
**Output -** 4

#### 5. Incrementing counter -

Run the following the command and see the results -

count=2
count=`expr $count + 1`
**Output -** 3