> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Escape

> This article explains shell globbing, escape characters, and how to manage filename patterns using wildcards and literals.

When working in the shell, special characters like `?`, `*`, and `[ ]` are interpreted by the globbing engine for filename matching. Preceding these characters with a backslash (`\`) or quoting them forces the shell to treat them as literal characters.

<Callout icon="lightbulb" color="#1CB2FE">
  Using an escape (`\`) or quotes disables globbing for the next character or entire string. This gives you precise control over filename creation and listing.
</Callout>

## 1. Creating Sample Files

First, generate files whose names differ only by the first letter:

```bash theme={null}
$ touch sail hail mail fail tail
$ ls
fail hail mail sail tail
```

## 2. Wildcard vs. Literal `?`

### 2.1 Using the `?` Wildcard

The `?` matches exactly one character. Attempting to create `?ail` without escaping:

```bash theme={null}
$ touch ?ail
$ ls
fail hail mail sail tail
```

No new file appears because `?ail` expanded to all existing matches (`fail`, `hail`, etc.).

### 2.2 Escaping `?` for Literal Filenames

To create a file literally named `?ail`:

```bash theme={null}
$ touch \?ail
$ ls
?ail fail hail mail sail tail
```

## 3. Listing Files with a Leading `?`

You can retrieve the `?ail` file by escaping or quoting the pattern:

```bash theme={null}
$ ls \?ail
?ail

$ ls "?ail"
?ail
```

Both methods disable globbing and match the literal filename.

## 4. Mixing Literals and Wildcards

Assume these files exist:

```bash theme={null}
$ touch hail fail mail \?ail
$ touch hailTwo failTwo mailTwo \?ailTwo
$ ls
?ail ?ailTwo fail failTwo hail hailTwo mail mailTwo
```

To list all files starting with a literal `?ail`:

```bash theme={null}
$ ls \?ail*
?ail  ?ailTwo
```

Here, `\?ail*` treats `\?` as literal `?` and `*` as the wildcard for any suffix.

<Callout icon="triangle-alert" color="#FF6B6B">
  Be cautious: unescaped wildcards can match unintended files. Always check your patterns with `echo` or `ls` before running destructive commands.
</Callout>

## 5. Merging Globs into a Single Pattern

For files named `Pail`, `Pail*`, and `PailTwo`:

```bash theme={null}
$ touch Pail Pail* PailTwo
$ ls
Pail Pail* PailTwo
```

You can match them all using:

```bash theme={null}
$ ls Pail*
Pail Pail* PailTwo
```

The `*` wildcard expands to zero or more characters following `Pail`.

## 6. Quick Reference Table

| Special Character | Behavior                | Escaped Form | Example        |
| ----------------- | ----------------------- | ------------ | -------------- |
| `?`               | Single-character match  | `\?`         | `touch \?file` |
| `*`               | Zero or more characters | `\*`         | `ls Pail\*`    |
| `[` `]`           | Character set           | `\[` `\]`    | `ls \[abc\]*`  |

## Summary

* A backslash (`\`) or quotes disables globbing for the next character or entire string.
* Use wildcards (`?`, `*`, `[ ]`) without escaping to match patterns.
* Combine escaped literals and wildcards for precise filename operations.

## Links and References

* [GNU Bash Manual – Pattern Matching](https://www.gnu.org/software/bash/manual/html_node/Pattern-Matching.html)
* [Bash Guide: Filename Expansion](https://mywiki.wooledge.org/Globbing)

<CardGroup>
  <Card title="Watch Video" icon="video" cta="Learn more" href="https://learn.kodekloud.com/user/courses/advanced-bash-scripting/module/a9d9ba2b-0baf-4c13-b60b-f6ce9cf97abd/lesson/a6c0b385-2275-4130-a9a9-fd35cd516de1" />
</CardGroup>