creating shell in c code example
Example: how to make a shell in c for beginners
int main(void) {
for (;;) {
char input[PRMTSIZ + 1] = { 0x0 };
char *ptr = input;
char *args[MAXARGS + 1] = { NULL };
int wstatus;
// prompt
printf("%s ", getuid() == 0 ? "#" : "$");
fgets(input, PRMTSIZ, stdin);
// ignore empty input
if (*ptr == '\n') continue;
// convert input line to list of arguments
for (int i = 0; i < sizeof(args) && *ptr; ptr++) {
if (*ptr == ' ') continue;
if (*ptr == '\n') break;
for (args[i++] = ptr; *ptr && *ptr != ' ' && *ptr != '\n'; ptr++);
*ptr = '\0';
}
// built-in: exit
if (strcmp(EXITCMD, args[0]) == 0) return 0;
// fork child and execute program
signal(SIGINT, SIG_DFL);
if (fork() == 0) exit(execvp(args[0], args));
signal(SIGINT, SIG_IGN);
// wait for program to finish and print exit status
wait(&wstatus);
if (WIFEXITED(wstatus)) printf("<%d>", WEXITSTATUS(wstatus));
}
}