bash), this is what solutions that use COLUMNS/ ROWS variables do. Telnet has its own affordances for querying the screen size, but of course this only works if people connect to your application via the telnet client, not really an option in most cases. Operating system dependent, and assumes you are connected to a TTY device. These are databases with terminal information, which you can query for instance with tput. if someone is using cmd.exe this likely won't work. This seems like a relatively safe assumption for a CLI program, but e.g. This is what this solution does, it assumes you are talking over stdin/stdout to a terminal emulator that honors these escape codes. There are really four different ways that I know of to achieve this, but they all make certain assumptions about the environment the program is running in, or the terminal device/emulator it is talking to. I first saw this used in the Lanterna library. Now watch stdin, you should receive a sequece that looks like [25 80R', where 25 is the row count, and 80 the columns. You can 'fix' this by running export COLUMNS LINES before you run your Java application. Indeed, in the case of a remote console connected via telnet protocol, there is no way to get the actual terminal dimensions to the user's shell.ĮDIT: Just to add that if the user changes the dimensions of his/her xterm on Linux after launching a Java app, the Java app won't be notified, and it won't see the new dimensions reflected in its copy of the LINES and COLUMNS environment variables!ĮDIT 2: My mistake: LINES and COLUMNS are bash shell variables, and they are not exported to the environment by default. While these variables are automatically updated when you resize some 'terminal emulator' windows, this is not always the case. )įor example, on a Linux system you can typically find out the notional terminal dimensions from the LINES and COLUMNS environment variables. (See other answers for approaches that work some of the time and/or on some platforms.

Indeed, there are situations where it is not possible to know what the real console width is. There are no reliable cross-platform solutions to this problem.

Eclipse ssh shell display line width