Your shell should:
• Not interpret unclosed quotes or unspecified special characters like \ or ; 🟢
• Not use more than one global variable, think about it and be ready to explain why you do it 🟢
• Show a prompt when waiting for a new command 🟢
• Have a working History 🟢
• Search and launch the right executable (based on the PATH variable or by using relative or absolute path) 🟢
◦ 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 🟢
• ’ inhibit all interpretation of a sequence of characters 🟢
• " inhibit all interpretation of a sequence of characters except for $ 🟢
◦ < should redirect input.
◦ > should redirect output.
◦ “<<” read input from the current source until a line containing only the de- limiter is seen. it doesn’t need to update history!
◦ “>>” should redirect output with append mode.
• Pipes | The output of each command in the pipeline is connected via a pipe to the input of the next command.
• Environment variables ($ followed by characters) should expand to their values 🟢
• $? should expand to the exit status of the most recently executed foreground pipeline 🟢
◦ ctrl-C print a new prompt on a newline 🟢
◦ ctrl-D exit the shell 🟢
◦ ctrl-\ do nothing 🟢