TTYS(5) File Formats Manual TTYS(5)
ttys - terminal initialization data
The ttys file is read by the init program and specifies which terminal
special files are to have a process created for them which will allow
people to log in. It contains one line per special file.
The first character of a line is either `0' or `1'; the former causes
the line to be ignored, the latter causes it to be effective. The sec‐
ond character is used as an argument to getty(8), which performs such
tasks as baud-rate recognition, reading the login name, and calling
login. For normal lines, the character is `0'; other characters can be
used, for example, with hard-wired terminals where speed recognition is
unnecessary or which have special characteristics. (Getty will have to
be fixed in such cases.) The remainder of the line is the terminal's
entry in the device directory, /dev.
init(8), getty(8), login(1)