simple_shell > Team project

Start -> Display prompt -> Read command line -> Check if command is a built-in (cd, exit, setenv, unsetenv, env, alias) -> If built-in, execute built-in -> If not built-in, check if command exists in PATH -> If command exists, fork and execute command -> Wait for child process to complete -> Display prompt -> Repeat

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+------------------+ +--------------------+ | Start | | End | | | | | | Display prompt | | Display prompt | | and wait for | | and exit shell | | user input | | | +------------------+ +--------------------+ | ^ v | +------------------+ Command doesn't exist | | Parse input and | <--------------------------------+ | execute command | or execution fails +------------------+ | | | v Command exists +------------------+ and execution succeeds | Handle built-in | <----------------+ | commands | or exec external program +------------------+ | v +------------------+ | Handle commands | | separator | | operators | | and variable | | replacement | +------------------+ | v +------------------+ +------------------+ | Handle comments | +---------------> | Handle file mode | +------------------+ +------------------+

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