# Bash Check if a String Contains a Substring Using Regex

> Use Bash's regex match operator (=~) or wildcard pattern matching with double brackets to check if a string contains a specific substring or character

**URL:** https://sentry.io/answers/check-that-a-string-contains-a-substring-in-bash/

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## The Problem

How can I check whether a string contains a substring using a Bash script?

## The Solution

We can do this in two ways. First, we can use Bash's regular expression matching operator (`=~`):

```bash
string='Hello world!';

if [[ $string =~ "world" ]]; then
  echo "Found 'world' in string."
fi
```

Alternatively, we can use wildcard matching:

```bash
string='Hello world!'

if [[ $string == *"world"* ]]; then
  echo "Found 'world' in string."
fi
```

While either method will work equally well for this simple case, the regular expression method is more powerful, as we can replace "world" with any regular expression. For example, the code below uses the same regular expression to check the string for an exclamation point or a question mark:

```bash
exclamation='Hello world!';
question='Hello world?';

if [[ $exclamation =~ !|\? ]]; then
  echo "The string matches!"
fi

if [[ $question =~ !|\? ]]; then
  echo "The string matches!"
fi
```

You can learn more about how to use regular expressions at [Regular-Expressions.info](https://www.regular-expressions.info/).

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*Source: [sentry.io/answers/check-that-a-string-contains-a-substring-in-bash/](https://sentry.io/answers/check-that-a-string-contains-a-substring-in-bash/)*