Implementation of ps-file report

psfiles = []  # plot files in PostScript format
...
while m <= m_max:
    case = 'tmp_m_%g' % m
    ...
    psfiles.append(os.path.join(case,case+'.ps'))
    ...
...
s = 'epsmerge -o tmp_mruns.ps -x 2 -y 3 -par ' + \
    ' '.join(psfiles)
failure, output = commands.getstatusoutput(s)