CodeCrafters CodeCrafters

Build your own Shell

Learn about parsing shell commands, executing programs and more

Start Building
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A shell is the program that interprets what you type into the terminal. It reads your commands, runs programs, and prints their output. Popular examples are Bash and ZSH.

In this challenge, you'll build your own shell from scratch.

Your shell will run a REPL, parse commands, spawn processes, and more.

What exactly will I build?
What exactly will I learn?
Why should I build such a project?
What are the pre-requisites for this challenge?

Stages

Print a prompt
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Handle invalid commands
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REPL
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The exit builtin
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The echo builtin
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The type builtin: builtins
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The type builtin: executable files
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Run a program
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Navigation

The pwd builtin
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The cd builtin: Absolute paths
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The cd builtin: Relative paths
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The cd builtin: Home directory
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Quoting

Single quotes
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Double quotes
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Backslash outside quotes
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Backslash within single quotes
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Backslash within double quotes
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Executing a quoted executable
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Redirection

Redirect stdout
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Redirect stderr
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Append stdout
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Append stderr
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Autocompletion

Builtin completion
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Completion with arguments
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Missing completions
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Executable completion
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Multiple completions
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Partial completions
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Pipelines

Dual-command pipeline
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Pipelines with built-ins
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Multi-command pipelines
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History

The history builtin
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Listing history
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Limiting history entries
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Up-arrow navigation
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Down-arrow navigation
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Executing commands from history
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History Persistence

Read history from file
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Write history to file
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Append history to file
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Read history on startup
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Write history on exit
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Append history on exit
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