The cleverer among you will espy the problem below immediately
$ export DATE=`date` $ echo $(DATE) bash: DATE: command not found
In my half-caffeinated state, it took several minutes of frustration to figure out what was wrong:
$(DATE) is a Make-style variable; in Bash,
$(DATE) is the same as
`DATE` (a command substitution). The correct token is
$ echo $DATE Tue Apr 15 11:08:38 EDT 2008
I apologize for inflicting my stupidity upon you.