CAT (Christopher, Andy, Theo) Shell

Shell Features

• Current Working Directory and Username in the Shell line.
• Executes commands using execvp.
• ";" separates different commands.
• Redirections
  • < and > indicate reading from a file to standard in and writing to a file from standard out respectively.
  • >> indicate writing and appending to a file.
  • Redirection behavior is similar to bash.
• Piping using |.
• Multiple redirections and pipes are supported on the same line.
• cd to different directories, including the user root directory and directories from the user root directories using "~"
• History
  • View previously entered commands in a list with history.
  • Enter a previously entered command with history [list number]:
    • eg:

    catsh$ history 69
    

    • This also works with negative numbers, in order to do the last command or a command done two entries ago. eg:

    catsh$ history -420
    

Launch Codes

Cloning the Project

Run:

$ git clone https://github.com/andylin2004/cat-shell.git

Building the Project

Ensure that you have gcc installed on your system. Run:

$ cd /path/to/cat-shell
$ make

Running the Project

Run:

$ cd /path/to/cat-shell
$ make run

Alternatively, you can also run:

$ cd /path/to/cat-shell
$ ./shell

Features Attempted

• Using Arrow Keys as a method to call previous functions and to move text field cursor between characters, as intercepting key inputs would've been too complicated for us to do.
• Using Tab in the same way as Bash. This would involve intercepting key inputs, and we had issues with this.
• Redirection behavior found on Zsh.

Noted Bugs

• Pressing the arrow buttons will generate the ascii keys, instead of moving the cursor or going through the history.
• If there is a \ in front of a space, the space will not be cancelled out.

Function Headers

int main();
void executeLine(char *input);
void cd(char **args);
char **redirectionParseAndSetup(char **input);
void executeCommand(char **commands, int pipes);
void executeCommandFork(char **commands, int start, int end, int pipeNum);
void closePipes();
void writeCommandToHistory(char *command);
void readHistory();
void printHistory();
void runHistory(char* input);
char ** parse_args(char *code, char delim);
int countDelimiters(char *code, char delim);
int arrayOfStringsLength(char **array);
char *standardizeString(char *oldString);
int lengthOfArray(char **array);
char * squigglyToHomeDirectory(char* string);