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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>
#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};
// DEFAULT SHELL COMMANDS
// exit() command
void exit_program()
{
exit(0);
}
// pwd command
void list_directories()
{
struct dirent **namelist;
int n;
n = scandir(".", &namelist, NULL, alphasort);
if (n == -1)
{
perror("scandir");
exit(EXIT_FAILURE);
}
while (n--)
{
printf("%s\n", namelist[n]->d_name);
free(namelist[n]);
}
free(namelist[n]);
exit(EXIT_SUCCESS);
}
// echo emulation command, without variables
void echo(char *command, char *argv)
{
if (strcmp(command, "echo") == 0)
{
printf("argv");
}
}
char **save_history(char *user_input)
{
char **command_history;
for (CURRENT_HISTORY_INDEX; CURRENT_HISTORY_INDEX < MAX_HISTORY; CURRENT_HISTORY_INDEX++)
{
for(CURRENT_COMMAND_INDEX; CURRENT_COMMAND_INDEX < MAX_COMMAND_LENGTH; CURRENT_COMMAND_INDEX++)
{
command_history[CURRENT_HISTORY_INDEX][CURRENT_COMMAND_INDEX] = user_input[CURRENT_COMMAND_INDEX];
}
}
return command_history;
}
// 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("SHELL> ");
scanf("%s", input);
if (strcmp(input, "exit") == 0)
exit_program();
}
return 0;
}
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