This project is a simplified shell. It was written in C and we were limited in the functions we were allowed to use.

The requirements were:

• Display a prompt when waiting for a new command.
• Have a working history.
• Search and launch the right executable (based on the PATH variable or using a relative or an absolute path).
• Not use more than one global variable. Think about it. You will have to explain its purpose.
• Not interpret unclosed quotes or special characters which are not required by the subject such as \ (backslash) or ; (semicolon).
• Handle ’ (single quote) which should prevent the shell from interpreting the meta- characters in the quoted sequence.
• Handle " (double quote) which should prevent the shell from interpreting the meta- characters in the quoted sequence except for $ (dollar sign).
• Implement redirections:
  • '<' should redirect input.
  • '>' should redirect output.
  • '<<' should be given a delimiter, then read the input until a line containing the delimiter is seen. However, it doesn’t have to update the history!
  • '>>' should redirect output in append mode.
• Implement pipes (| character). The output of each command in the pipeline is connected to the input of the next command via a pipe.
• Handle environment variables ($ followed by a sequence of characters) which should expand to their values.
• Handle $? which should expand to the exit status of the most recently executed foreground pipeline.
• Handle ctrl-C, ctrl-D and ctrl-\ which should behave like in bash.
• In interactive mode:
  • ctrl-C displays a new prompt on a new line.
  • ctrl-D exits the shell.
  • ctrl-\ does nothing.
• Your shell must implement the following builtins:
  • echo with option -n
  • cd with only a relative or absolute path
  • pwd with no options
  • export with no options
  • unset with no options
  • env with no options or arguments
  • exit with no options

Other project partner:

https://github.com/Abdi-29