Using If...Else Statements in Bash
This section explains how to use conditional statements in Bash scripting.
If Statements
If statements allow you to execute code based on a condition. If the condition is true, the code block will run.
The condition is enclosed in square brackets [ ] and the statement ends with fi , which is if spelled backward, marking the end of the if block.
Example: If Statement
# Basic if statement
num=15
if [ $num -gt 10 ]; then
echo "Number is greater than 10"
fiIf...Else Statements
If...else statements provide a way to execute one block of code if a condition is true and another block if it is false.
The else keyword introduces the alternative block, and the statement ends with fi .
Example: If...Else Statement
# If...else statement
num=8
if [ $num -gt 10 ]; then
echo "Number is greater than 10"
else
echo "Number is 10 or less"
fiElif Statements
Elif statements allow you to check multiple conditions in sequence. If the first condition is false, the next one is checked.
The elif keyword stands for "else if," and the statement still ends with fi .
Example: Elif Statement
# If...elif...else statement
num=10
if [ $num -gt 10 ]; then
echo "Number is greater than 10"
elif [ $num -eq 10 ]; then
echo "Number is exactly 10"
else
echo "Number is less than 10"
fiNested If Statements
Nested if statements allow you to place an if statement inside another if statement, enabling more complex logic.
Each if block must be closed with its own fi .
Example: Nested If Statement
# Nested if statement
num=5
if [ $num -gt 0 ]; then
if [ $num -lt 10 ]; then
echo "Number is between 1 and 9"
fi
fi