4.9 what='plot_bz'

With this option the code writes a script to make a plot of the Brillouin zone and of the path (the default one or the one given in input). The script must be read by the asymptote code, available at http://asymptote.sourceforge.net/. In many Linux distributions this code is available as a separate package, but it is not installed by default.
The following variables control the plot:

lasymptote  : if .TRUE. asymptote is called from within the program
              and the pdf file with a plot of the BZ is produced
              Default: logical .FALSE.
flasy       : initial part of the name of the file where the asymptote script
              is written and of the name of the pdf file.
              Default: character(len=*) 'asy_tmp'
asymptote_command  : the command that invokes asymptote and produces the 
              pdf file of the BZ.
              Default: character(len=*) 'asy -f pdf -noprc flasy.asy'
npx         : used only in the monoclinic cell, this parameter is needed
              to determine the shape of the Brillouin zone. The default
              value is usually large enough, but for particular shapes of
              the monoclinic Brillouin zone it could be small. If the
              code stops with an error asking to increase npx, double 
              it until the error disappears.
              Default: integer 8

The structure of the solid can be seen using the XCrySDen code that can read the input file of pw.x. You can find the code at http://www.xcrysden.org/. thermo_pw produces also a file in the xsf format called prefix.xsf, where the variable prefix is given in the input of pw.x. This can be useful when the nonequivalent atomic positions and the space group are given in the input of pw.x. To see an xsf file, give the command xcrysden -xsf file.xsf.

With this option the code produces also a file with the X-ray powder diffraction intensities for the solid. A plot shows the scattering angles and the relative intensity of each peak. Note that this plot is made using a superposition of atomic charges, not the self-consistent charge. By setting the flag lformf=.TRUE. the atomic form factors of all the atomic types used to calculate the intensities are plotted. By setting the flag lxrdp=.TRUE. the intensities plot is done also after the cell optimization and after a self-consistent calculation for the options that support it. The variables that control these plots are:

lambda      : The X-ray wavelength (in A) used to calculate the scattering 
              angles.
              Default: Cu alpha line 1.541838 A if lambda_element is empty
lambda_elem : The anode element, used to set the X-ray wavelength.
              Supported elements 'Cr', 'Fe', 'Co', 'Cu', 'Mo'.
              NB: lambda must be zero to use lambda_elem, otherwise the value
              of lambda given in input is used.
              Default: character(len=2) ' ' 
flxrdp      : name of the file where the scattering angles and intensities 
              are written.
              Default: character 'output_xrdp.dat'
flpsxrdp    : name of the postscript file with the X-ray diffraction
              spectrum.
              Defaults: character 'output_xrdp'
lxrdp       : if .TRUE. compute the xrdp also after the cell optimization
              with all the options mur_lc_... with the uniformly strained
              atomic positions and after the scf calculation if supported
              by the option. 
              Default: logical .FALSE.
lformf      : if .TRUE. plot also the form factor of each atom type
              present in the solid. Note that the atom type is recognized
              from the atom name in the thermo_pw input. The name
              must coincide with the symbols in the periodic table. 
              (Cu, H, Li, Li1, ... are correct, CU, LI, H1 ... are wrong)
              Default: logical .FALSE.
smin        : minimum value of s used in the atomic form factor plot.
              Default: real 0.0
smax        : maximum value of s used in the atomic form factor plot.
              Default: real 1.0
nspoint     : number of points in which the atomic form factor is calculated.
              Default: integer 200
lcm         : when .TRUE. the code uses the Cromer-Mann coefficients form
              the International Tables of Crystallography to
              compute the atomic form factors, otherwise uses the 
              Doyle-Turner or Smith-Burge parameters.
              Default: logical .FALSE.
flformf     : name of the file in which the atomic form factor is written. 
              The code adds a number to each file name and creates a file
              per atom type.
              Defaults: character 'output_formf.dat'
flpsformf   : name of the postscript file with the atomic form factor.  
              The code adds a number to each file name and creates a file
              per atom type.
              Defaults: character 'output_formf'