Can you put conditional logic in the glogin.sql file?

I would like to place the following in my glogin.sql file but it causes problems when I'm running sql scripts from a shell script.  The host part of the command gets the width of the current window and writes it out to a file with the "set linesize" command.

I would like to somehow put some login in to say that if the width of the window is determined to be zero (i.e. a sql script is being run) then don't run the set linesize command.  Any ideas?

HOST "echo "set linesize $(stty -a | head -n1|cut -f7 -d' '|cut -f1 -d';')" > /tmp/.tmp.sql