The invalid option is because fgets() keeps the ‘n’ when you press enter, try this
if(!fgets(line, BUFFER_LEN, stdin))
break;
size_t length = strlen(line);
if (line[length – 1] == ‘n’)
line[length – 1] = ‘ ’;
when you are trying to call ls -l you are passing “-ln” as the option, hence the message.
You will have to change
strcmp(line, “exitn”)
to
strcmp(line, “exit”)
#include
#include
#include
#include
#include
#define BUFFER_LEN 1024
int main(){
char user_input[BUFFER_LEN]; //get command line
char* argv[120]; //user command
int argc ; //argument count
char* path= “/bin/”; //set path at bin
char file_path[50];//full file path
while(1){
printf(“Simple Shell>> “); // Greeting shell during startup
if(!fgets(user_input,BUFFER_LEN, stdin)){
break; //break if the command length exceed the defined BUFFER_LEN
}
size_t length = strlen(user_input);
if(length == 0){
break;
}
if (user_input[length – 1] == ‘n’){
user_input[length – 1] = ‘ ’; // replace last char by ‘ ’ if it is new line char
}
//split command using spaces
char *token;
token = strtok(user_input,” “);
int argc=0;
if(token == NULL){
continue;
}
while(token!=NULL){
argv[argc]=token;
token = strtok(NULL,” “);
argc++;
}
argv[argc]=NULL;
strcpy(file_path, path); //Assign path to file_path
strcat(file_path, argv[0]); //conctanate command and file path
if (access(file_path,F_OK)==0){ //check the command is available in /bin
pid_t pid, wpid;
int status;
pid = fork();
if (pid == 0) { //child process
if (execvp(file_path,argv) == -1) {
perror(“Child proccess end”);
}
exit(EXIT_FAILURE);
}
else if (pid > 0) { // parent process
wpid = waitpid(pid, &status, WUNTRACED);
while (!WIFEXITED(status) && !WIFSIGNALED(status)){
wpid = waitpid(pid, &status, WUNTRACED);
}
}
else {
perror(“Fork Failed”); //process id can not be null
}
}
else {
printf(“Command is not available in the binn”); //Command is not available in the bin
}
}
}