A01637391-homework-03

labs/03/simple-shell2.c

@@ -0,0 +1,77 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#define MAX_LINE 80 /* Maximum characters per command line */
+#define STDIN 0
+#define STDOUT 1
+
+const char* Tux =
+    "    __      \n"
+    " -=(o '.    \n"
+    "    '.-.\\   \n"
+    "    /|  \\\\  \n"
+    "    '|  ||  \n"
+    "     _\\_):,_" ;
+
+
+void displayTux(){
+    int lengthTux = strlen(Tux);
+
+    for (int i = 0; i < lengthTux; i++) {
+        if (Tux[i] == '\n') {
+            write(STDOUT, "\n", 1); // Print a newline character
+        } else {
+            write(STDOUT, &Tux[i], 1); // Print the character
+        }
+    }
+}
+
+int main(void) {
+    char args[MAX_LINE/2 + 1]; // Buffer for user input
+    int should_run = 1; // Flag to control the shell loop
+
+    while (should_run) {
+        displayTux(); // Print Tux at the beginnign of each line
+        printf(">>> "); // Prompt string
+
+        // Read user input
+        fgets(args, MAX_LINE/2 + 1, stdin); // Prevents buffer overflow, and read() does not
+
+        // Check if the user wants to exit the shell
+        if (strcmp(args, "exit\n") == 0) break;
+
+        pid_t pid = fork(); // Create a child process
+        if (pid < 0) {
+            fprintf(stderr, "Error forking, errno = %d\n", errno);
+            return 1;
+        } else if (pid == 0) { // Child process
+            args[strlen(args) - 1] = '\0'; // Remove the newline character at the end
+            char* argv[MAX_LINE/2 + 1];
+            char* token = strtok(args, " "); // Tokenize the input
+
+            int i = 0;
+            while (token != NULL) {
+                argv[i] = token;
+                token = strtok(NULL, " ");
+                i++;
+            }
+            argv[i] = NULL;
+
+            // Execute the command
+            if (execvp(argv[0], argv) == -1) {
+                perror("execvp"); // Print an error message if execvp fails
+                exit(EXIT_FAILURE);
+            }
+        } else { // Parent process
+            int status;
+            wait(&status); // Wait for the child process to complete
+        }
+    }
+
+    return 0;
+}