### 3.10 `GFORTRAN_LIST_SEPARATOR`—Separator for list output

This environment variable specifies the separator when writing list-directed output. It may contain any number of spaces and at most one comma. If you specify this on the command line, be sure to quote spaces, as in

         $ GFORTRAN_LIST_SEPARATOR='  ,  ' ./a.out

when `a.out` is the compiled Fortran program that you want to run. Default is a single space.