Learn Bash If, Elif and If Else with examples

introduction

Bash scripts are mainly a should have software for system administrators, builders and Linux clients. They supply a useful technique to automate duties and enhance effectiveness. One of many many key parts of bash scripting are conditional statements, much like if, else if, and if else (elif) statements. These conditional statements permit Linux customers to make selections based mostly totally on quite a few circumstances throughout the bash script, offering flexibility and manageability. On this article, we’ll uncover tips about the right way to use if, elif, and else statements in bash scripts, together with associated examples.

Learn to use If Assertion in Bash Script

The commonest and fundamental conditional assertion utilized in bash scripting is the if assertion. It’s used to confirm whether or not a sure scenario is completely happy or not. The syntax for utilizing the if assertion in bash is as follows:

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

Throughout the above syntax, the is carried out on the situation that the be completely happy. Let’s illustrate this with an instance:

#!/bin/bash

echo -n Enter a amount: 
study num

if (( $num -lt 20 ))
then
  echo The price is decrease than 20.
fi

On this occasion, the individual is prompted to enter an quantity. If the entered worth is lower than 20, the message The worth is lower than 20. is printed as output.

Learn to use the If Else assertion in Bash Script

Typically, you might wish to take an operation if the scenario shouldn’t be completely happy. In such circumstances, you must use the else conditional assertion along with the if assertion. This offers extra flexibility to your bash script. The syntax for utilizing the else assertion is as follows:

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

Let’s take this instance for example:

#!/bin/bash

echo Please enter your age:
study age

if ( $age -ge 18 ); then
  echo Congratulations! You are eligible to vote.
else
  echo Sorry, you are not eligible to vote however.
fi

Learn to use Else If (Elif) in Bash Script

Whereas the if-else conditional meeting is helpful for checking a scenario and operating a job accordingly, it is most likely not sufficient if you must verify for a lot of circumstances. In such circumstances, you must use the else if or elif assertion. This lets you verify for a lot of circumstances 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 think about an occasion:

#!/bin/bash

echo -n Enter a fruit determine: 
study fruit

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

Conclusion

Conditional statements are an important a part of bash scripting, permitting customers to make selections based mostly totally on quite a few circumstances. On this article, we have explored using if, elif, and else statements in bash scripts. By mastering these conditional statements, you may enhance the efficiency and dealing with of your bash scripts. Whether or not or not you are a sysadmin, developer, or Linux individual, understanding conditional statements is vital to environment friendly scripting.

FAQs

What are conditional statements in bash scripting?

Conditional statements in bash scripts are used to make selections based mostly primarily on quite a few circumstances. They permit shoppers to hold out explicit directions or carry out sure operations relying on whether or not a scenario is true or false.

Why are conditional statements very important in bash scripts?

Conditional statements have flexibility and dealing with in bash scripts. They permit clients to automate duties and make choices based mostly totally on explicit circumstances, enhancing effectivity and productiveness.

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

The syntax for the if assertion in bash is as follows:

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

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

The else assertion in bash scripting is used to specify a block of code that must be executed when the scenario specified throughout the if assertion is fake.

How do you utilize the elif assertion in bash?

The elif assertion in bash is used to check a lot of circumstances after the preliminary if assertion. If the scenario contained in the elif assertion is true, the corresponding block of code is executed. If not one of the circumstances are true, the code specified throughout the else block is executed.