I know that it is quite easy to figure out a terminal's size parameters via the stty -a command. When using local CLI PHP scripts, there is no problem at all on grabbing that output via system() or so.
But I am trying the same thing via a php script started from an ssh command. Sadly, all that stty ever returns is:
stty: standard input: Invalid argument.
The calling code is:
exec('stty -a | head -n 1', $query);
echo $query[0];
So the question is: If I can output to the terminal and read input from it (e.g. can fread() from STDIN and fwrite() to STDOUT in PHP, shouldn't stty also have valid STDIN and STDOUT?
Use ssh -t:
% php ~/src/termtest.php
speed 9600 baud; 39 rows; 127 columns;
% ssh localhost php ~/src/termtest.php
stty: stdin isn't a terminal
% ssh -t localhost php ~/src/termtest.php
speed 9600 baud; 39 rows; 127 columns;Connection to localhost closed.
SSH does not pass in a fully functional terminal by default. Shells and ncurses seem to be able to get them somehow, but to launch something that needs one directly from SSH you need to set -t.
For the same reason you can e.g. launch tmux (or screen) by ssh'ing to a server and then typing tmux at the prompt or through ssh -t _server_ tmux but not through sh _server_ tmux.