Guide · Agent skill
How to use the Shell Scripting Expert agent skill
Updated · written with AI from the project's own documentation and checked against our catalogue data
The Shell Scripting Expert skill is a set of written guidelines that tells your AI agent how to write shell scripts the way a careful systems engineer would. It is aimed at developers writing deployment or backup scripts, sysadmins who need scripts to run on both Linux and macOS, and students learning good shell practice. After reading this guide you will know what the skill changes, how to install it, how to ask for scripts so the skill is used, and where its limits are.
Shell Scripting ExpertRightNow-AI/openfang · Apache-2.0 Download the skill Quick start
- 1Download the ZIP. Download the skill ZIP from this page. The package contains SKILL.md.
- 2Choose where to install. Use ~/.claude/skills/ for a personal install or .claude/skills/ inside a project for a project-only install.
- 3Unzip the skill. Unzip the download into the chosen folder so that SKILL.md sits inside the skill folder.
- 4Or upload in the Claude apps. If you use the Claude apps, go to Settings → Capabilities → Skills and upload the skill there.
- 5Ask for a script in plain language. Describe the job, the target system and what must not fail silently.
- 6Review the output and test it. Read the script, then run it on the platforms you care about before using it for real work.
What does the shell-scripting skill make the agent do?
With the skill installed, the agent writes Bash and POSIX shell scripts with failure handling built in. Its guidelines ask for scripts that fail fast on errors, quote variables, clean up temporary files with traps, and send log messages to stderr so stdout stays clean for data.
The skill also tells the agent to choose between Bash-specific syntax and POSIX-portable syntax depending on the target system, and to avoid common mistakes such as parsing ls output or using eval on user input.
- Starts Bash scripts with set -euo pipefail
- Quotes variable expansions such as "$var" and "${array[@]}"
- Uses mktemp and a trap on EXIT for temporary files
- Uses a logging function that writes timestamped messages to stderr
- Uses meaningful exit codes: 0 for success, 1 for general errors, 2 for usage errors
Install the skill from the ZIP download
The skill ships as a ZIP download from this page. Its only file is SKILL.md. You can install it in one of two places, depending on whether you want it for all your projects or just one.
For a personal install that applies everywhere, unzip the download into ~/.claude/skills/. For a project-only install, unzip it into the .claude/skills/ folder inside your project. Either way, the folder should contain the SKILL.md file.
If you use the Claude apps, you can instead upload the skill under Settings → Capabilities → Skills.
- Personal: unzip into ~/.claude/skills/
- Project only: unzip into .claude/skills/ in your project
- Claude apps: Settings → Capabilities → Skills, then upload
How do you trigger the skill with a natural request?
You do not need a special command. Ask for a script in plain language and say what it is for, what system it runs on, and what must not fail silently. Mentioning the job (deployment, backup, automation) and the platform (Linux, macOS, or both) helps the agent pick the right level of portability.
Because the skill is written around error handling and portability, requests that name those concerns tend to get the most useful output.
- Write a backup script for my Postgres data directory that must not fail silently.
- Write a deploy script that runs on both Linux and macOS and uses only POSIX syntax.
- Rewrite this script to be safe with filenames containing spaces.
- Review this Bash script for unquoted variables and missing error handling.
What kinds of scripts work well with this skill?
The skill is strongest on small to medium scripts that glue commands together. Its guidelines are explicit that shell excels at combining commands rather than handling complex logic.
Examples of work it covers include argument parsing with getopts or a while loop with case, cleaning up temporary files, running background jobs in parallel and waiting for them, and checking that required environment variables and files exist before the script continues.
- Deployment scripts that check inputs before acting
- Backup scripts that must report failures
- Scripts that loop over files safely, including names with spaces
- Idempotent setup steps that check whether a tool is installed before installing it
What are the safety notes and limits?
The skill is only written guidelines. According to its description, it does not run scripts and does not use the network, and it lists no requirements. Nothing it produces is executed or verified by the skill itself.
The skill assumes you will test scripts on your target platforms. It warns that macOS ships BSD versions of common tools with different flags, so a script that works on Linux may not work on a Mac. It also suggests considering Python or another language once a script grows past about 200 lines.
- Runs scripts: no
- Uses network: no
- Requires: nothing listed
- Cannot run or check code on your machine
- Test on each target platform before relying on a script
What people use it for
- A deployment script that stops on the first error and cleans up temporary files
- A backup script that logs timestamped messages to stderr
- A portable script that runs on both Linux and macOS
- A file-processing loop that handles filenames containing spaces safely
- A learning aid: reviewing a script to see why quoting and error handling matter
Frequently asked questions
How do I install the shell scripting agent skill?
Download the ZIP from this page and unzip it into ~/.claude/skills/ for a personal install, or into .claude/skills/ inside a project for a project-only install. If you use the Claude apps, you can upload it under Settings → Capabilities → Skills instead.
Does the shell-scripting skill cost anything or require a licence?
The skill is published under the Apache-2.0 licence, as listed on this page. The source lists no requirements to use it, so you only need an agent that supports skills.
Does the skill run my scripts or access the internet?
No. The skill is only a set of written guidelines. It does not run scripts and does not use the network, so it cannot test code on your machine.
Why does the agent say my script might not work on macOS?
The skill notes that macOS ships BSD versions of many tools with different flags than GNU coreutils. It recommends testing on target platforms or sticking to POSIX-only features.
When should I not use this skill?
Its guidelines suggest that scripts longer than about 200 lines may be better written in Python or another language. It is also not a substitute for testing a script on the specific machine it will run on.
How is this different from just asking an agent for a script?
The skill gives the agent a consistent set of rules, such as failing fast, quoting variables, using traps for cleanup, and avoiding eval on user input. Without it, the agent may or may not follow these conventions.
New agent skills, repos and AI tools — every week
The best new skills and open-source projects, the fastest-growing repos, and one free prompt. Five minutes to read. Unsubscribe anytime.
Our verdict
Use this skill if you want an agent to write shell scripts that fail loudly, handle cleanup and filenames properly, and stay portable where needed. Pick a different approach if you need complex application logic, or if you need a script verified on a specific machine, since the skill cannot run or test anything itself.
Download the skill