You can do as suggested, limiting their shell environment while they are in
isql, but beware that, at least in 4.0 isql, that means they also cannot
run shell commands that are on the menu, such as
"cd somewhere; sperform something". We had to put the SHELL=newshell;export
command IMMEDIATELY before the sperform, on the menu action line, or in the
shell script calling that ONE form. But it does indeed work.
Ann