---
title: Add a valid shebang as the first line of executable shell scripts
description: Datadog, the leading service for cloud-scale monitoring.
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  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > Add a valid shebang as the first line of executable shell scripts
---

# Add a valid shebang as the first line of executable shell scripts

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## Metadata{% #metadata %}

**ID:** `bash-code-quality/missing-shebang`

**Language:** Bash

**Severity:** Notice

**Category:** Code Style

## Description{% #description %}

Without `#!` on line one, a script run directly is executed by whatever `/bin/sh` points to (often dash or ash), not necessarily Bash. Bash-only syntax can then fail in confusing ways or behave differently than on your interactive shell. Put a valid interpreter line first, for example `#!/usr/bin/env bash` or an absolute path like `#!/bin/bash`, matching what you actually need.

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```bash
# not a shebang
echo "if this were line 1 there would still be no interpreter path after #!"
true
```

## Compliant Code Examples{% #compliant-code-examples %}

```bash
#!/bin/bash
echo ok
```
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