EXTRACT

        LAS\EXTRACT [X1 X2 [Unit]] [/INDEX]

    In  its  default mode, EXTRACT copies R into T, extracts a subsection of
    R, and save the result in R. If the option /INDEX is present, or if  SET
    ACTION  is  INDEX,  a subsection of each observation in the index is ex-
    tracted and saved in the output file.

    Without arguments, the cursor is invoked (if available)  to  define  the
    subsection range. If the arguments X1 and X2 are present, the subsection
    is defined by this range, in the given Unit (if any) or  by  default  in
    the  current  X axis unit (SET UNIT). X2 can be indifferently greater or
    lower than X1, and Unit is a single  character  in  the  four  C)hannel,
    V)elocity, F)requency or I)mage.

    If the range overlaps the input spectrum limits, a warning is raised and
    the missing data is filled with the blanking value. Requesting  a  range
    off the input spectrum is an error. The command FIND /FREQUENCY can help
    you to build an index with spectra  overlapping  one  frequency  or  one
    range of frequencies.

    Only regularly sampled X axes are supported.