Most useful programs:

spplot.pro       - plots a spectrum, handling breaks in orders
speplot.pro      - overplots errors
spadd.pro        - adds two spectra (or subtracts with /minus)
spdivide.pro     - divides one spectrum by another (or a scalar)
sptimes.pro      - multiplies one spectrum by another (or by a scalar)

spavg.pro        - find the average flux in a spectrum between two wavelengths
spcex.pro        - measures the strength of a spectral feature after fitting
                   a continuum underneath it
spex.pro         - measures the strength of a feature given a spectrum and 
                   estimated continuum 
spjoin.pro       - joins (concatenates) two spectra 
spsmooth.pro     - applies boxcar smoothing to a spectrum (or specified orders)

The package contains many other routines, including file wrappers for the
above, routines called by the above, routines written for very specified
purposes, and outmoded routines.  Here's a full list:

sp2gplot.pro     - overplots 2 Gaussians
spcexw.pro       - outmoded version of spcex, only finds equivalent widths
spchisq.pro      - determines the summed chi-squared error in a wavelength range
spclean.pro      - cleans spikes in spectral data
spcoadd.pro      - coadds spectral FITS files - outdated, use spfcoadd.pro
spcolor.pro      - calculates a color index from a spectrum
spcompare.pro    - plots a spectrum and a comparison spectrum
spcontp.pro      - fits a Planck function as a continuum to a spectrum
spcont.pro       - fits a polynomial as a continuum to a spectrum
spcut.pro        - cuts a spectrum (or segment) to a specified wavelength range
spdust.pro       - fits a Planck or Engelke function, returns the difference
spengelke.pro    - fits an Engelke function to a spectrum
speqf.pro        - outmoded version of spex to measure the equivalent flux of a
                   spectral feature
spexw.pro        - outmoded version of spex to measure the equivalent width of
                   a spectral feature
spfcoadd.pro     - coadds a list of spectral FITS files
spfdivide.pro    - file wrapper for spdivide.pro
spfitlines.pro   - fits a series of line segments to a spectrum
spfjoin.pro      - file wrapper for spjoin.pro
spfmean.pro      - file wrapper for spmean.pro
spfnodjoin.pro   - file wrapper for spjoin, and either sppair or spmean.pro
spfnorm.pro      - file wrapper for spnorm.pro
spfpair.pro      - file wrapper for sppair.pro
spfplot.pro      - file wrapper for spplot.pro
spfse.pro        - file wrapper for spse.pro
spfspot.pro      - file wrapper for spspot.pro
spftimes.pro     - file wrapper for sptimes.pro
spgaussfit.pro   - fits a Gaussian to a region in a spectrum
spgauss.pro      - generates a Gaussian on a given spectral grid
spgplot.pro      - plots a spectrum and a Gaussian
spgridlo.pro     - regrids a spectrum, best if going to a lower resolution grid
spgridspline.pro - regrids a spectrum using the IDL routine cspline
spmax.pro        - finds the maximum flux in a spectrum
spmean.pro       - averages two spectra into one
spmin.pro        - find the minimum flux in a spectrum
spnoise.pro      - estimates the noise in a spectrum
spnorm.pro       - normalizes a spectrum, each segment separately if needed
sppair.pro       - combines two spectra in the same wavelength range into one
                   removes spikes which only appaer in one of the spectra
sppeak.pro       - finds the wavelength of maximum flux in a spectrum
spphot.pro       - integrates the produce of a spectrum and a filter function
spplanck.pro     - fits a Planck function to a spectrum
spplotbat.pro    - batch-mode wrapper for spplot.pro
sppoly.pro       - fits a polynomial to a spectrum
spreplace.pro    - replaces flux at a specified wavelength
sprj.pro         - converts a spectrum to Rayleigh-Jeans units
spscale.pro      - finds the scaling factor which minimizes chi-squared
                   difference between two spectra
spsc.pro         - finds modified SE index for a spectrum
spse.pro         - finds SE index for a spectrum
spsort.pro       - sorts by wavelength, can remove duplicate wavelengths
spspot.pro       - finds the flux in a spectrum at a specified wavelength
spstackbat.pro   - batch-mode co-adding of spectra with normalization
spsum.pro        - numerically integrates a spectrum between two wavelengths
sptem.pro        - regrids one spectrum to another
sptrim.pro       - trims a spectrum, segment-by-segment
spzap.pro        - removes a wavelength element from a spectrum
spz.pro          - redshifts a spectrum

fix_spikes.pro  generic routine to find and replace spikes in data array
wr_spfits.pro
