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About Online Shell Script Formatter

Paste your shell script, press "Format", and get clean, consistent output powered by `shfmt`. Ideal for DevOps pipelines, dotfiles, container entrypoints, and production-ready deployment scripts. No installation, no login – just readable shell code ready to commit.

Why Use This Shell Script Formatter

  • Instant formatting for POSIX sh, Bash, mksh and related shells
  • shfmt-style rules for indentation, spacing and case/esac blocks
  • Designed to support options like indent size, tabs vs spaces and redirect spacing
  • Paste raw code or upload `.sh`, `.bash`, `.ksh`, `.mksh`, or `.bats` files
  • Perfect companion for CI/CD pipelines, Docker entrypoints and dotfiles
  • Formatted via a secured backend running shfmt-style logic – no local install required
  • One-click copy or download of the cleaned script

🛠️ How to Format Your Shell Scripts Online for shell-script-formatter

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1. Paste or Upload Your Script

📥 Paste your shell code into the editor, or drag-and-drop a `.sh`, `.bash`, `.ksh`, `.mksh` or `.bats` file. Syntax highlighting makes it easy to spot structure and commands.

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2. (Optional) Tweak Advanced Settings

⚙️ If your project uses custom style rules, adjust indentation or other advanced options when they are available in the UI. Otherwise, the default profile already matches common shfmt practices.

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3. Format Your Script

✨ Click **Format** to send your script to the secure formatting API. It rewrites indentation, spacing and certain constructs while preserving behavior.

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4. Copy or Download the Result

📤 Copy the formatted script back into your editor, or download it as a `.sh` file ready for git, CI, or production deploys.

Technical Specifications

Supported Formats & Extensions

Supports common Bourne-style shell dialects you encounter in real-world systems:

Format / DialectTypical ExtensionDescription
POSIX sh.shPortable shell scripts compatible with /bin/sh
Bash.sh, .bashGNU Bash scripts and interactive helpers
Korn shell (ksh).kshKorn shell scripts in legacy environments
mksh.mkshMirBSD Korn shell scripts
Bats tests.batsShell-based test suites using Bats

Formatting Behavior (shfmt-Style)

The backend formatter follows shfmt-style rules for consistent shell layout.

AspectBehaviorBenefit
IndentationNormalizes indent on `if`, `for`, `while`, `case`, functions and subshellsEasier to visually parse control flow and nesting.
SpacingAdds spaces around `=` in assignments and around binary operators where appropriateReduces visual noise and accidental parsing mistakes.
RedirectsSupports spacing around `>`, `>>`, `<` according to shfmt-style conventionsImproves readability of file redirections.
Case blocksAligns `case`, pattern branches and `esac` consistentlyPrevents deeply nested or compressed case statements.
Idempotent outputRunning the formatter again yields the same resultAllows safe integration in pre-commit hooks and CI.

Input Limits & Size

Designed to be fast and predictable even on non-trivial scripts.

ParameterLimit / BehaviorNotes
Max input size (text)≈ 2 MBScripts larger than this are better formatted locally with shfmt.
Max file size (upload)≈ 5 MBIdeal for most deployment scripts and utility collections.
EncodingUTF-8 recommendedConvert legacy encodings like ISO-8859-1 before formatting.

Execution Model

The formatter runs via a secured backend using shfmt-style logic.

AspectBehaviorNotes
TransportHTTPS call to the `/api/shell-script-formatter` endpointPrevents eavesdropping while your script is being formatted.
Timeout~25 seconds per requestAvoids runaway jobs on extremely large or pathological inputs.
SemanticsWhitespace and layout onlyYour script logic is preserved; only formatting is changed.

CLI Equivalent with shfmt

Want the same behavior in your terminal or CI pipeline? Use `shfmt` directly:

Linux / 🍎 macOS / 🪟 Windows (via WSL or Go)

Install shfmt using Go

go install mvdan.cc/sh/v3/cmd/shfmt@latest

Installs the `shfmt` binary into your Go bin directory (e.g. `~/go/bin`).

Format a shell file with 2-space indent

shfmt -i 2 -w script.sh

Overwrites `script.sh` with consistently formatted output.

Format and print to stdout

shfmt -i 4 script.sh

Uses 4-space indentation and prints to stdout without modifying the file.

Check formatting in CI (no changes)

shfmt -d scripts/

Shows a diff for files that would be reformatted; exits non-zero if changes are needed.

Add a `shfmt -d` step in your CI pipeline or a pre-commit hook so every script stays clean and consistent automatically.

Practical Use Cases for Shell Formatting

DevOps & CI/CD Pipelines

Keep mission-critical scripts readable, reviewable and production-safe.

  • Clean up deployment and rollback scripts before merging to `main`.
  • Normalize hooks in `.git/hooks`, `scripts/` and CI helpers.
  • Format Docker entrypoints and container bootstrap scripts.
shfmt -i 2 -w ./scripts/deploy.sh
shfmt -i 2 -w ./scripts/*.sh

Team Collaboration & Open Source

Avoid style arguments and focus on logic in reviews.

  • Apply a single style across all contributors' shell scripts.
  • Make onboarding easier by keeping dotfiles and helpers neat.
  • Reduce noisy diffs by standardizing indentation and spacing.
shfmt -w hooks/*.sh
shfmt -i 2 -ci -bn -w .

Learning & Teaching Shell Scripting

Show best practices to students and junior developers.

  • Clean up examples before putting them in slides or documentation.
  • Auto-format student submissions to focus feedback on semantics.
  • Demonstrate how layout affects readability and bug spotting.

❓ Frequently Asked Questions

🔍What is shfmt?

`shfmt` is an open-source command-line formatter for shell scripts created by mvdan. It parses your shell code and rewrites it with consistent indentation, spacing and structure for POSIX sh, Bash and similar dialects.

⚙️Can I choose how many spaces to indent?

Yes. In CLI usage you can control indentation with the `-i` flag (for example `-i 2` or `-i 4`). This online tool is designed to support equivalent indentation preferences via its formatting backend.

🚫Does this web tool overwrite my file?

No. The formatter returns the cleaned script in the browser. You decide whether to copy it into your editor or download it as a new file. Your originals remain untouched unless you overwrite them yourself.

💬Does it understand Bash-specific syntax?

Yes. The underlying shfmt-style engine supports common Bash constructs as well as POSIX sh, plus additional shells such as mksh and ksh.

🔒Is it safe to format sensitive scripts here?

For general-purpose scripts, this tool is convenient and secure. For scripts containing highly sensitive data (embedded secrets, internal infrastructure details, etc.), it is usually safer to run shfmt locally or inside your own CI environment.

Pro Tips

Best Practice

Run shfmt before every commit so your git history focuses on real changes, not whitespace.

Best Practice

Combine `shfmt -d` with CI to block merges when scripts aren’t properly formatted.

Best Practice

Pair this formatter with ShellCheck to catch both style and logic issues in your shell scripts.

Best Practice

Keep your shebangs (`#!/usr/bin/env bash`) consistent across all scripts to avoid subtle portability issues.

Additional Resources

shfmt GitHub Repository
Documentation
Bash Guide (mywiki.wooledge.org)
Documentation
ShellCheck: Lint Your Shell Scripts
Documentation

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