支持cat命令

mkrtos_user/lib/letter-shell/demo/mkrtos/shell_fs_ext.c

@@ -1,4 +1,6 @@
 #include "shell.h"
+#include "cons_cli.h"
+
 #include <stdio.h>
 #include <dirent.h>
 #include <unistd.h>
@@ -29,3 +31,29 @@ int ls(int argc, char *agrv[])
     return 0;
 }
 SHELL_EXPORT_CMD(SHELL_CMD_PERMISSION(0) | SHELL_CMD_TYPE(SHELL_TYPE_CMD_MAIN), ls, ls, ls command);
+int cat(int argc, char *argv[])
+{
+    if (argc != 2)
+    {
+        return (-1);
+    }
+
+    FILE *fp;
+    int c;
+
+    if ((fp = fopen(argv[1], "r")) == NULL)
+    {
+        return (-2);
+    }
+
+    while ((c = fgetc(fp)) != EOF)
+    {
+        cons_write(&c, 1);
+    }
+    cons_write_str("\n");
+    fclose(fp);
+
+    return 0;
+}
+SHELL_EXPORT_CMD(SHELL_CMD_PERMISSION(0) | SHELL_CMD_TYPE(SHELL_TYPE_CMD_MAIN), cat, cat, cat command);
+