Added run_scripts exercises

exercises/run_scripts/main.c

@@ -0,0 +1,59 @@
+/* This program executes a sequence of Bash scripts
+ * in sequential order. Each script is run in a child
+ * process, and the parent prints the exit status.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int main(int argc, char *argv[])
+{
+	if (argc < 2) {
+		fprintf(stderr, "usage: %s <file1>...\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	for (int i = 1; i < argc; i++) {
+		const char *script_name = argv[i];
+		printf("execute script %d: %s\n", i, script_name);
+
+		/* fork process for execute script itself */
+		pid_t pid = fork();
+		switch (pid) {
+		case -1:
+			perror("fork");
+			exit(EXIT_FAILURE);
+			break;
+		case 0:
+			// child executes the current script
+			if (execlp("/bin/bash", "bash", script_name,
+				   (char *)NULL) == -1) {
+				perror("execlp");
+				exit(EXIT_FAILURE);
+			}
+			break;
+		default:
+			// parent waits for the child process
+			int status;
+			if (waitpid(pid, &status, 0) == -1) {
+				perror("waitpid");
+				exit(EXIT_FAILURE);
+			}
+			if (WIFEXITED(status)) {
+				printf("script %s exited with code %d\n",
+				       script_name, WEXITSTATUS(status));
+			} else if (WIFSIGNALED(status)) {
+				printf("script %s terminated by signal %d\n",
+				       script_name, WTERMSIG(status));
+			} else {
+				printf("script %s did not exit normally\n",
+				       script_name);
+			}
+			break;
+		}
+	}
+
+	return EXIT_SUCCESS;
+}