I think this is related:
in my ~/.bashrc :
# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

if you add (to .bashrc)
export LINES
export COLUMNS

then your script will probably work without modification


Walter Dnes wrote:
> 3) Speaking of bash scripts, I ran into something not-so-minor today,
> which prompted this message. Environmental variables ${LINES} and
> ${COLUMNS} exist at the commandline, but not in a bash script. Typing
>
> echo ${LINES} ${COLUMNS}
>
> ...at the commandline works, but the script
>
> #!/bin/bash
> echo ${LINES} ${COLUMNS}
>
> ...returns nothing. This happens in xterm and urxvt under X, and even
> in a textmode console outside of X. This kills a script of mine that
> USED TO WORK under Gentoo.
>