How to Use elif in Bash: Syntax and Examples

In bash, use elif to add multiple conditions in an if statement. It works like "else if" in other languages, letting you check another condition if the previous if or elif was false.

Syntax

The elif statement in bash is used between if and else to test additional conditions. The structure is:

• if: starts the first condition
• elif: tests another condition if the previous was false
• else: runs if all previous conditions are false

bash

if [ condition1 ]; then
  # commands if condition1 is true
elif [ condition2 ]; then
  # commands if condition2 is true
else
  # commands if none of the above are true
fi

Example

This example script checks a number and prints if it is positive, zero, or negative using if, elif, and else.

bash

#!/bin/bash
number=5

if [ "$number" -gt 0 ]; then
  echo "The number is positive"
elif [ "$number" -eq 0 ]; then
  echo "The number is zero"
else
  echo "The number is negative"
fi

Output

The number is positive

Common Pitfalls

Common mistakes when using elif include:

• Forgetting spaces around brackets [ ] which causes syntax errors.
• Not closing the if block with fi.
• Using elif without a preceding if.
• Confusing elif with else if (bash requires elif as one word).

bash

# Wrong: missing spaces
if [ "$num" -gt 0 ]; then
  echo "Positive"
elif [ "$num" -eq 0 ]; then
  echo "Zero"
fi

# Correct:
if [ "$num" -gt 0 ]; then
  echo "Positive"
elif [ "$num" -eq 0 ]; then
  echo "Zero"
fi

Quick Reference

Remember these tips when using elif in bash:

• Always use elif as one word, not else if.
• Put spaces around brackets and operators.
• Close the entire conditional block with fi.
• You can have multiple elif blocks to check many conditions.

Key Takeaways

Use elif to check multiple conditions after an initial if in bash.

Always put spaces around brackets and operators in condition tests.

Close your conditional blocks with fi to avoid syntax errors.

elif must be one word; do not write else if.

You can use multiple elif statements to handle many cases.