diff --git a/docs/books/admin_guide/03-commands.md b/docs/books/admin_guide/03-commands.md
index 5cc27feb93..a727e0dc76 100644
--- a/docs/books/admin_guide/03-commands.md
+++ b/docs/books/admin_guide/03-commands.md
@@ -491,7 +491,7 @@ The `ls` command, however, has a lot of options (see `man`):
 | `-d`                                                         | Displays information about a directory instead of listing its contents.                                                              |
 | `-g`                                                         | Displays UID and GID rather than owner names.                                                                                        |
 | `-h`                                                         | Displays file sizes in the most appropriate format (byte, kilobyte, megabyte, gigabyte, ...). `h` stands for Human Readable.         |
-| `-s`                                                         | Displays the size in bytes (unless `k` option).                                                                                      |
+| `-s`                                                         | Displays the number of blocks occupied by the file. One block equals 400K.                                                                                      |
 | `-A`                                                         | Displays all files in the directory except `.` and `.`.                                                                              |
 | `-R`                                                         | Displays the contents of subdirectories recursively.                                                                                 |
 | `-F`                                                         | Displays the type of files. Prints a `/` for a directory, `*` for executables, `@` for a symbolic link, and nothing for a text file. |