The issue-file (/etc/issue or the file set with the -f option) may contain certain escape codes
to display the system name, date and time etc.
All escape codes consist of a backslash () immediately followed by one of the letters explained below.
\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, eg. 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 OS, eg. 1.1.9.
\t : Insert the current time.
\u : Insert the number of current users logged in.
\U : Insert the string “1 user” or “ users” where is the number of current users logged in.
\v : Insert the version of the OS, eg. the build-date etc.
We can display /etc/issue using the less command/more command/most command or cat command or bat command:
bat /etc/issue
more /etc/issues
cat /etc/issue
Source: Linux display or change a pre-login message /etc/issue file