operator
file string-expression exists
An operator that tests whether a named file exists. Useful for avoiding overwriting a file that already exists with a new one.
For example, the following shows how a file...exists
test can be used to avoid overwriting an existing file:
global stream error-strm ... do when file "errors.log" exists put #error "File errors.log already exists.%n" put #error "Please delete or rename it before running this program.%n" halt with 1 else open error-strm as file "errors.log" done