rshell

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#UCR CS100 Assignment Fall 2016

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Description of Command Shell

• Basic and limited terminal

• Executes user's command input

• Does not read in or execute comments following # symbol

• Accepts Command Chaining 'echo name && mkdir test ; ls'

  • '&&': Executes previous then the latter command if previous is successful

  • '||': Executes following command only if the previous fails

  • ';' : Executes following command no matter what

• Displays error messages if failed execution at any point

• Added test command implementation, runs with keyword "test" or the bracket symbols as well

  • flag "-e" to check if the file or directory exists (default flag)
  • flag "-f" to check if the file or directory exists and is a regular file
  • flag "-d" to check if the file or directory exists and is a directory
  • example: "test -e Test.h" or "[ Command.h ]
  • Command chaining is compatible
  • "test -e main.cpp && echo taco"

• Use of precedence using parentheses

• Separate sets can be used "(echo hello && echo name) || (echo world && echo llama)"

• Nested parentheses can be used "(echo hey && (echo this || echo yes))"

• Exits the terminal using the command 'exit'

• Added cd command implementation

  • may use cd, cd -, or cd path

Known Bugs

• The command following || is not executed if the first command is not recognize

• Include quotation marks when echoing

• No variations of the word exit can be used 'Exit' or 'EXIT'

• No built in bash commands work

• Commands are still executed if user enters single connectors '&' '|'