CSE shell assignment

PTSH

This is a basic shell written using C.

Running the code:

1.cd to the directory the shell is present in.

2.Type the command make.

3.Enter ./a.out to run the shell.

Code:

1. main.c is the file which runs runShell() and is the source file. runShell() handles the inputs of the prompt and calls the necessary functions based on the command input.

2. prompt.c is solely responsible for displaying the prompt. It calls printPrompt().

3. cd.c behaves as the cd function. It implements the chdir() function.

4. utils.c contains the echo and pwd functions. echo simply prints the input given. pwd calls getcwd to output the absolute path of the curent directory.

5. ls.c behaves as the ls function. It also handles the -l -a -al/la flags. It calls the scandir() function to enlist the files in the directory. To handle the -l flag, stat() command is used to obtain the required data of the file.

6. pinfo.c prints the current process information. It reads the data at the /proc/pid/status and /proc/pid/exe to get the necessary information.

7. exec.c uses the wait() and fork() processes to run background and foreground processes. It also calls waitpid() and signal() for detecting when a process and ended and uses flags to check if it has ended normally.

8. nwatch.c read the data at the /proc/meminfo and /proc/interrupts to get the data. It checks whether the user has entered a character by using the getchar() command.

9. history.c writes the commands entered in a file and reads them when the history() function is called.

10. Makefile defines the compilation rules so that multiple gccs don't have to be called each time.