Add (untested) mv implementation.

src/mv.c

@@ -20,8 +20,11 @@
  *     --version    Print version information and exit.
  */
 
+#include <libgen.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
+#include <sys/stat.h>
 #include "boreutils.h"
 
 static int prompt(char *dest) {
@@ -35,9 +38,41 @@ static int prompt(char *dest) {
     return 0;
 }
 
-static int would_overwrite(char *src, char *dest) {
-    (void)src;
-    return access(dest, F_OK) + 1;
+// If dest is a directory, returns `<dest>/<basename of src>`.
+// Otherwise, returns `<dest>`.
+static char *normalize_dest(char *src, char *dest) {
+    struct stat statbuf;
+    if (stat(dest, &statbuf) != 0) {
+        // `dest` doesn't exist.
+        return dest;
+    }
+
+    if (!S_ISDIR(statbuf.st_mode)) {
+        // `dest` is a file (not a directory).
+        return dest;
+    }
+
+    // Beyond this point, `dest` is known to be a directory.
+    // This means we need `<dest>/<basename of src>`.
+
+    // First, get the basename of `src`.
+    char *base_name = basename(src);
+    size_t base_name_size = strlen(base_name);
+
+    size_t dest_size = strlen(dest);
+    // <dest size> + <1 for slash> + <basename size> + <1 for null terminator>
+    char *full_dest = malloc(sizeof(char) * (dest_size + 1 + base_name_size + 1));
+    memset(full_dest, 0, dest_size + 1 + base_name_size + 1);
+
+    strncpy(full_dest, dest, dest_size + 1);
+    if (dest[dest_size - 1] != '/') {
+        full_dest[dest_size] = '/';
+        strncpy(full_dest + dest_size + 1, base_name, base_name_size + 1);
+    } else {
+        strncpy(full_dest + dest_size, base_name, base_name_size + 1);
+    }
+
+    return full_dest;
 }
 
 int main(int argc, char **argv) {
@@ -77,8 +112,9 @@ int main(int argc, char **argv) {
     }
 
     for (; i < argc - 1; i++) {
-        if (should_prompt && would_overwrite(argv[i], dest)) {
-            if (prompt(dest) == 0) {
+        char *normalized_dest = normalize_dest(argv[i], dest);
+        if (should_prompt && access(normalized_dest, F_OK) == 0) {
+            if (prompt(normalized_dest) == 0) {
                 continue;
             }
         }