I have a line in my ~/.bash_profile
(from Ubuntu) that might do the trick:
# check the window size after each command and, if necessary, # update the values of LINES and COLUMNS. shopt -s checkwinsize
You can run this first in the Terminal window to see if it works, and if it does, add it to your own ~/.bash_profile
.
Alternatively, you could reset iTerm's preferences. With iTerm not running, move ~/Library/Preferences/com.googlecode.iterm2.plist
to your Desktop (to back it up), and reopen iTerm. You'd have to replicate your old settings this way, but it might be easier to fix your problem in this way.