smbpasswd: add page (#3382)

pages/linux/smbpasswd.md

@@ -0,0 +1,20 @@
+# smbpasswd
+
+> Change a user's SMB password.
+> Samba users must also have a local Unix account.
+
+- Change the current user's SMB password:
+
+`smbpasswd`
+
+- Add a specified user to Samba and set password(user should already exist in system):
+
+`smbpasswd -a {{user_name}}`
+
+- Modify an existing Samba user's password:
+
+`smbpasswd {{user_name}}`
+
+- Delete a Samba user:
+
+`smbpasswd -x {{user_name}}`