LFIND

        [WEEDS\]LFIND [SPECIES [FMIN FMAX]] [/SORTBY ORDER] [/ENERGY ENERGY]
    [/AIJ AMIN]

    Find the lines within a frequency range and create  a  line  index.  The
    command  looks  for  the lines between FMIN and FMAX in the database se-
    lected with the USE IN command. If not specified, the values of FMIN and
    FMAX are taken from the current spectra.

    Arguments:
        SPECIES   the name of the species. Default is "All".

        FMIN      the minimum frequency in MHz.

        FMAX      the maximum frequency in MHz

    Options:
        /SORTBY   sort the lines according to ORDER, which can be any combi-
                  nation of "frequency", "energy" and "aeinstein",  and  all
                  the subsequent permutations.

        /ENERGY   refine  the  search to lines with upper level energy lower
                  than ENERGY, expressed in Kelvins.

        /AIJ      refine the search to lines  with  einstein  A  coefficient
                  greater than AMIN, expressed s-1.