Bash Tools

Guidelines for proper tool selection when executing commands or modifying files.

Core Principle

Use specialized file tools for file operations. Use Bash only for actual shell commands.

Never use Bash to circumvent file operation permissions. If Write tool is blocked, that's intentional - do not work around it with echo, cat, or heredocs.

Tool Selection Decision Tree

Need to create/overwrite a file?
├── YES → Use Write tool (NOT echo/cat/heredoc)
└── NO → Continue...

Need to edit part of a file?
├── YES → Use Edit tool (NOT sed/awk)
└── NO → Continue...

Need to read file contents?
├── YES → Use Read tool (NOT cat/head/tail)
└── NO → Continue...

Need to search file contents?
├── YES → Use Grep tool (NOT grep/rg in Bash)
└── NO → Continue...

Need to find files by pattern?
├── YES → Use Glob tool (NOT find/ls in Bash)
└── NO → Continue...

Is this an actual shell command? (git, npm, docker, make, etc.)
├── YES → Use Bash tool
└── NO → Reconsider - probably need a file tool

Prohibited Patterns

These patterns attempt to circumvent Write tool permissions and MUST NOT be used:

| Pattern | Why It's Wrong | Correct Approach | |---------|---------------|------------------| | echo "content" > file.py | Bypasses Write permissions | Use Write tool | | cat << 'EOF' > file.py | Heredoc bypasses permissions | Use Write tool | | printf '%s' "$content" > file | Same as echo bypass | Use Write tool | | tee file.py <<< "content" | Redirect bypass | Use Write tool |

See references/permission-patterns.md for comprehensive examples.

Tool References

• Write Tool - Creating and overwriting files
• Bash Tool - Running shell commands
• Edit Tool - Modifying existing files
• Read Tool - Reading file contents

When Write Tool is Blocked

If the Write tool is blocked for a file:

1. Accept the block - It exists for a reason
2. Ask the user if they want to allow the operation
3. Do NOT attempt to use Bash to write the file instead

The permission system protects the user. Circumventing it defeats its purpose.

Updating This Skill

When encountering new permission circumvention patterns or tool usage issues, see references/updating-skill.md.

Quick Reference

| Task | Tool | NOT This | |------|------|----------| | Create file | Write | echo > file | | Edit file | Edit | sed -i | | Read file | Read | cat file | | Search content | Grep | grep pattern | | Find files | Glob | find . -name | | Git commands | Bash | - | | npm/yarn | Bash | - | | docker/make | Bash | - | | Run tests | Bash | - |