Using make will create the shell executable.
Simply run it with ./shell
---Main instructions---
• 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).
• 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-\
◦ ctrl-C displays a new prompt on a new line.
◦ ctrl-D exits the shell.
◦ ctrl-\ does nothing.
• 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