Fortran 95 and dbx must be in the same case-sensitive or case-insensitive mode:
If the source has a variable named LAST, then in dbx, both the print LAST or print last commands work. Fortran 95 and dbx consider LAST and last to be the same, as requested.
Compile and debug in case-sensitive mode using -U. The default value of the dbx input_case_sensitive environment variable is then true.
If the source has a variable named LAST and one named last, then in dbx, print last works, but print LAST does not work. Fortran 95 and dbx distinguish between LAST and last, as requested.