PA3 - The Pioneer Shell: Resubmission Due 11/20 at 11:59pm

If you want to resubmit PA3, please read this section carefully. You need to pass all the tests in the original PA3, while also implementing an extra functionality.

Implement pish as originally described. Also update pish to support a new built-in command !! that re-executes the last non-!! command entered by the user.

The !! command should also be recorded in the command history, but should not affect what the "last" command is.

For example, if the user enters the following commands in sequence:

▶ history
1 history
▶ !!
1 history
2 !!
▶ pwd
/home/jpolitz/cse29fa25/pa3/Simple-Shell
▶ ls
Makefile  script.sh  pish  pish.c  pish.h  pish_history.c
pish_history.o  pish.o
▶ !!
Makefile  script.sh  pish  pish.c  pish.h  pish_history.c
pish_history.o  pish.o
▶ !!
Makefile  script.sh  pish  pish.c  pish.h  pish_history.c
pish_history.o  pish.o
▶ history
1 history
2 !!
3 pwd
4 ls
5 !!
6 !!
7 history

Errors

For each of the following errors, call the usage_error() function in the starter code and continue to the next iteration of the loop.

• If the user enters !! as the very first command (there is no last command to execute).
• If the user enters !! <anything> (if argc != 1).

Coding Style Resubmission

If you got a point off for coding style in the original PA3, you do not have to do the new functionality for that point.

Refer to the Piazza post for more details.