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#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <stdbool.h>
#include <linux/limits.h>
#define MAX_HISTORY 100
#define MAX_COMMAND_LENGTH 256
// static int CURRENT_COMMAND_INDEX = 0;
// static int CURRENT_HISTORY_INDEX = 0;
// static char *COMMAND_HISTORY[MAX_HISTORY] = { NULL};
void test_print()
{
printf("print to output");
}
// DEFAULT SHELL COMMANDS
// exit() command
void exit_program()
{
exit(0);
}
// ls command
void list_current_directories()
{
fork();
DIR *DIRECTORY_STREAM;
DIRECTORY_STREAM = opendir(".");
if (DIRECTORY_STREAM == NULL)
{
perror("ERROR_DIRECTORY_STREAM_EMPTY");
}
else
printf("%p", (&DIRECTORY_STREAM));
_exit(0);
}
char *print_working_directory()
{
char *current_working_directory = malloc(sizeof(char) * 100);
if(getcwd(current_working_directory, sizeof(current_working_directory) != 0))
{
return current_working_directory;
}
else
{
perror("getcwd() error");
return "ERROR";
}
}
// echo emulation command, without variables
char *echo(char *command)
{
char *argv = (char *)malloc(sizeof(char) * 4);
char *command_argument = (char *)malloc(sizeof(char) * 100);
int separation_index = 0;
for (int i = 0; i < sizeof(command); i++)
{
if (strcmp(&command[i], " ") == 0)
{
separation_index = i;
for ( int j = 0; j < separation_index; j++)
{
argv = &command[j];
}
}
}
if (strcmp(argv, "echo") == 0)
{
for (int i = separation_index + 1; i < (sizeof(command) - separation_index); i++)
{
if(strcmp(&command[i], "\0") != 0)
{
break;
}
else
{
strcpy(&command_argument[i - (separation_index - 1)], &command[i]);
}
}
}
return command_argument;
}
// GET USER INPUT
char * get_line()
{
char *line_read = malloc(sizeof(char) * MAX_COMMAND_LENGTH);
if (line_read)
{
free(line_read);
line_read = (char *)NULL;
}
scanf("%s", &(*line_read));
// if (line_read && *line_read)
// save_history(line_read);
return line_read;
}
int main(void)
{
char *input = malloc(sizeof(char *) * MAX_COMMAND_LENGTH);
while (true)
{
printf("\nSHELL> ");
scanf("%s", input);
if (strcmp(input, "exit") == 0)
exit_program();
else if(strcmp(input, "current_directory") == 0)
print_working_directory();
else if(strcmp(input, "test") == 0)
test_print();
else if(strcmp(input,"ls") == 0)
list_current_directories();
}
return 0;
}
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