When you first boot up your new LFS system, the logon screen will be nice and plain (as it should be in a bare-bones system). Many people however, will want their system to display some information in the logon message. This can be accomplished using the file /etc/issue.
The /etc/issue file is a plain text file which will also accept certain Escape sequences (see below) in order to insert information about the system. There is also the file issue.net which can be used when logging on remotely. ssh however, will only use it if you set the option in the configuration file and will also not interpret the escape sequences shown below.
One of the most common things which people want to do is to clear the screen at each logon. The easiest way of doing that is to put a "clear" escape-sequence into /etc/issue. A simple way of doing this is to do clear > /etc/issue. This will insert the relevant escape code into the start of the /etc/issue file. Note that if you do this, when you edit the file, you should leave the ^[c character on the first line alone.
The following escapes are recognized by agetty (the program which usually parses /etc/issue). This information is from man agetty where you can find extra information about the logon process.
The issue file can contain certain escape codes to display various information. All escape codes consist of a backslash (\) immediately followed by one of the letters explained below (so \d in /etc/issue would insert the current date).
b Insert the baudrate of the current line. d Insert the current date. s Insert the system name, the name of the operating system. l Insert the name of the current tty line. m Insert the architecture identifier of the machine, e.g., i486 n Insert the nodename of the machine, also known as the hostname. o Insert the domainname of the machine. r Insert the release number of the kernel, e.g., 2.4.16. t Insert the current time. u Insert the number of current users logged in. U Insert the string "1 user" or "<n> users" where <n> is the number of current users logged in. v Insert the version of the OS, e.g., the build-date etc.