Learn Bash If, Elif and If Else with Examples

Introduction

Bash script is important software program primarily for system directors, builders, and Linux purchasers. They supply a helpful method for automating duties and rising effectiveness. One of many many key elements of Bash scripting are conditional statements, akin to if, else if, and if else (elif) statements. These conditional statements permit Linux customers to carry out choices based mostly on a number of situations in a Bash script, offering flexibility and manageability. On this article, we’ll spotlight recommendations on the right method to make use of if, elif, and else statements in Bash scripts, together with associated examples.

Be taught to Use the If Assertion in Bash Script

The commonest and primary conditional assertion utilized in Bash scripting is the if assertion. It’s used to confirm whether or not a sure situation is glad or not. The syntax for utilizing an if assertion in bash is as follows:

if (( <scenario> ))
then
    <assertion>
fi

In the midst of the above syntax, that is accomplished on the situation that you’re completely comfortable. Allow us to clarify it with an instance:

#!/bin/bash

echo -n Enter a quantity: 
research num

if (( $num -lt 20 ))
then
  echo The value is lower than 20.
fi

From time to time, the particular person is prompted to enter a amount. If the worth entered is lower than 20, the message worth is lower than 20. is printed as output.

Be taught to Use the If Else Assertion in Bash Script

Normally, chances are you’ll wish to have an operation if the situation isn’t utterly favorable. In such conditions, you need to use an if assertion with an else conditional assertion. This supplies extra flexibility to your bash scripts. The syntax for utilizing else assertions is as follows:

if (( <scenario> ))
then
  <statement_to_execute_if_condition_is_true>
else
  <statement_to_execute_if_condition_is_false>
fi

Let’s take this instance for illustration:

#!/bin/bash

echo Please enter your age:
research age

if ( $age -ge 18 ); then
  echo Congratulations! You're eligible to vote.
else
  echo Sorry, you aren't eligible to vote nevertheless.
fi

Be taught to Use Else If (elif) in Bash Script

Whereas if-else conditional matching is helpful for checking a situation and working the motion accordingly, it’s in all probability not ample if you need to examine many situations. In such circumstances, you need to use an if or elif assertion in any other case. It permits you to confirm a number of situations and modify your bash script accordingly. The syntax for utilizing the elif assertion in Bash is as follows:

if ( condition_1 )
then
    <statements_to_follow_if_condition_1_is_true>
elif ( condition_2 )
then
    <statements_to_follow_if_condition_2_is_true>
else
    <statements_to_follow_if_all_conditions_are_false>
fi

Let’s consider a chance:

#!/bin/bash

echo -n Enter a fruit decide: 
research fruit

if ( $fruit = apple )
then
    echo It is an apple.
elif ( $fruit = banana )
then
    echo It is a banana.
else
    echo It is neither an apple nor a banana.
fi

conclusion

Conditional statements are an necessary a part of Bash scripting, permitting customers to make choices based mostly on a variety of situations. On this article, we explored utilizing if, elif, and else statements in Bash scripts. By mastering these conditional statements, you possibly can enhance the effectivity and dealing with of your Bash scripts. Whether or not you’re a system admin, developer or Linux particular person, understanding conditional statements is necessary for setting pleasant scripting.

inquiries to ask

What are conditional statements in bash scripting?

Conditional statements in bash scripts are primarily used to carry out choices based mostly on a number of situations. They permit shoppers to comply with particular directions or carry out sure operations relying on whether or not a situation is true or false.

Why are conditional statements so necessary in bash scripts?

Conditional statements have flexibility and are handled with bash scripts. They permit clients to automate duties and make choices based mostly on particular situations, enhancing effectivity and productiveness.

What’s the syntax for an if assertion in bash?

The syntax for an if assertion in Bash is as follows:

if (( <scenario> ))
then
    <assertion>
fi

What’s the perform of else assertion in bash scripting?

The else assertion is utilized in Bash scripting to specify a block of code that must be executed when the situation specified within the if assertion is simulated.

How do you employ the elif assertion in bash?

The elif assertion in Bash is used to check a number of circumstances after the preliminary if assertion. If the situation contained within the elif assertion is true, then the corresponding block of code is executed. If not one of the situations is true, the code specified within the else block is executed.