4.6 what='scf_bands'

With this option the code makes a self-consistent calculation followed by a band structure calculation. There is no image parallelization and no advantage to use several images. The output of the band structure calculation is further processed in order to produce a plot of the band structure. The zero of the energy is the highest valence band of the first k point in insulators and the Fermi energy in metals.
The energy bands plot can be modified by the following variables:

emin_input : minimum energy for the band dispersion plot (in eV).
             Default: real minimum of the bands
emax_input : maximum energy for the band dispersion plot (in eV).
             Default: real maximum of the bands
nbnd_bands : the number of bands in the band calculation
             Default: integer 2*nbnd, where nbnd is the number of bands 
             given in pw.x input or calculated by pw.x.
only_bands_plot: if the files with the bands and the representations
             are already on files, this option allows to change the 
             parameters of the plot (such as the maximum or minimum energy) and
             do another plot without additional calculation. If the files are
             missing and this variable is .TRUE. an error occurs. Note that
             using this option you cannot change the path.
             Default: logical .FALSE.
lsym       : if .TRUE. does the symmetry analysis of the bands
             Default: .TRUE.
enhance_plot: if .TRUE. writes on the band plot the point group labels,
             and colors with different background colors lines at the 
             zone border.
             Default: .FALSE.
long_path  : if .TRUE. plots the bands in all the Brillouin zone path. 
             Otherwise makes a faster calculation on a short path. 
             The short path is indicated also for two-dimensional layers 
             perpendicular to the z direction.
             Default: .TRUE.
old_path   : if .TRUE. use an alternative path, usually more similar to the one
             used in experimental papers (available only for a few lattices).
             Default: .FALSE.
path_fact  : A factor that multiply the number of points along each line of 
             the default path. Note that this is a real number so you can 
             also decrease the default number of points along each line.
             Default: real 1.0
filband    : file where the bands are written in the QE format
             Default: character(len=*) 'output_band.dat'
flpband    : file(s) where the bands are written in gnuplot format.
             Default: character(len=*) 'output_pband.dat'
flpsband   : postscript file with the electronic band structure
             Default: character(len=*) 'output_band'

Number of tasks for this option: 1.

By default, the bands are plotted along a fixed path in the Brillouin zone, but the user can modify this behavior giving the path at the end of the INPUT_THERMO namelist with the same format used for the pw.x input. The automatic path generation is not available for base-centered monoclinic and for triclinic Bravais lattices. For these lattices the path must be given explicitly. The following variables control the path:

q_in_band_form   : only the first and last point of each k path are given.
                 The weight of each k point is an integer, the number of 
                 points in the line that starts at this k point.
                 Default: logical .TRUE.
q_in_cryst_coord : the k - points are given in crystal coordinates.
                 For centered lattices the crystal coordinates refer
                 to the primitive cell (not the conventional one).
                 Same convention as in QE.
                 Default: logical .FALSE.
point_label_type : the label definition (see the BZ manual)
                 Default: SC
q2d              : the q points define a rectangle in reciprocal space.
                   See the QE guide for more details.
                 Default: logical .FALSE.
is_a_path        : if .TRUE. the q points are in a path in reciprocal 
                   space. This is usually the case except when q2d=.TRUE. 
                   or when the input points are in an arbitrary order.
                   Set this to .FALSE. only if you want to skip the plot
                   of the bands.
                 Default: logical .TRUE.

Note that the path cannot be given in the input of pw.x that must contain the information to generate the mesh of k points for the self-consistent calculation. An example for this option can be found in example02. If you give explicitly the path, be careful with options that require geometry changes (see below). Only automatic paths, or path given through letter labels are easily recalculated. The other paths could turn out to be correct only for one geometry.

It is also possible to separate the self-consistent and the band calculation, by running first thermo_pw.x using what='scf' and then running, on the same directory, thermo_pw.x using what='scf_bands'. The same input can be used in the two calculations, only the thermo_control file need to be changed. The number or processors and pools can be changed in the same cases in which this is possible in pw.x. You cannot however run twice thermo_pw.x on the same directory using what='scf_bands' and two different paths.