In this project, we created a simple UNIX command line interpreter called "sash". Sash prints a command prompt and waits for the user to type a command and press enter. This intepreter can handle standard commands and user-created executables as well as some builtin functions.
Entry Functions
| File | Function | Description |
|---|---|---|
| main_sash.c | main_sash | Tests interactivity of sash shell |
| enter_sash.c | enter_sash | Enter interactive mode of sash shell |
| enter_nonsash.c | enter_nonsash.c | Enter noninteractive mode of sash shell |
Essential Functions
| File | Function | Description |
|---|---|---|
| read_command.c | read_line | Reads the line entered into standard input and stores it in a buffer |
| split_line.c | split_line | Splits the line entered into standard input into a 2D array of strings |
| get_path.c | get_path | gets the PATH from the environment |
| tokenize.c | tokenize_path | Splits the PATH into individual directories |
| find_dir.c | find_dir | Finds the directory an executable is in and concatenates the command with the directory |
| execute.c | _execute | Executes non-builtin commands |
Builtin Functions
| File | Function | Description |
|---|---|---|
| builtins.c | run_builtin | Looks for the right builtin function and executes it |
| _env.c | _env | Prints the current environment |
| exit.c | exit_sash | Exits the Sash shell |
| chdir.c | _chdir | Changes the working directory |
String Manipulation/Counting Functions
| File | Function | Description |
|---|---|---|
| doubleptr_len | doubleptr_len | Counts the number of strings in a 2D array |
| str_cmp.c | str_cmp | Compares two strings and returns 0 if they are identical |
| str_len.c | str_len | Counts the length of a string and returns the length |
| str_str.c | str_str | Finds a substring in a string and returns that substring |
| str_cat.c | str_cat | Concatenates two strings together |
Memory Allocation and Free Functions
| File | Function | Description |
|---|---|---|
| double_ptr_list.c | double_ptr_list | Stores all allocated double pointers in a linked list |
| single_ptr_list.c | single_ptr_list | Stores all allocated pointers in a linked list |
| free_double_list.c | free_double_list | Frees all double pointers stored in linked list |
| free_single_list.c | free_single_list | Frees all single pointers stored in linked list |
Non-Function Files
| File | Description |
|---|---|
| sash.h | Header file containing all prototype functions and structs used in this project |
| man_1_simple_shell | man page for our program |
| AUTHORS | Lists individuals who contributed to this repository |
$ ls -l file.c
-rw-rw-r-- vagrant vagrant 501 Nov 16 01:06 file.c
Entering ls -l file.txt will display the permissions and details of file.c
$ echo hi
hi
Entering echo hi will print hi to the standard output
echo "ls -l" | ./sash
-rw-rw-r-- vagrant vagrant 501 Nov 16 01:06 file.c
Piping echo "ls -l" into ./sash (non-interactive mode) will print the same output as entering "ls -l" in interactive mode
Stefan Silverio & Allison Weiner