diff --git a/common/compare_dirs.py b/common/compare_dirs.py
new file mode 100755
index 0000000..21f8dc6
--- /dev/null
+++ b/common/compare_dirs.py
@@ -0,0 +1,439 @@
+#!/usr/bin/env python3
+#
+# compare_dirs.py <path>
+#
+#
+# Compare the format subdirectories of <path> and report on which files do not appear
+# in all of them.  If a directory has no files in it, then it is ignored.
+#
+# NOTE:  This script was not designed for files in the "ef_format" file structure.
+
+import os
+import sys
+
+def compare_dirs(path, styles, formats, debug):
+    do_cdl = True if 'cdl' in formats else False
+    do_gds = True if 'gds' in formats else False
+    do_lef = True if 'lef' in formats else False
+    do_mag = True if 'mag' in formats else False
+    do_maglef = True if 'maglef' in formats else False
+    do_verilog = True if 'verilog' in formats else False
+
+    try:
+         d1 = os.listdir(path + '/cdl')
+    except:
+         d1 = []
+    d1e = list(item for item in d1 if os.path.splitext(item)[1] == '.cdl')
+    d1r = list(os.path.splitext(item)[0] for item in d1e)
+    try:
+        d2 = os.listdir(path + '/gds')
+    except:
+        d2 = []
+    d2e = list(item for item in d2 if os.path.splitext(item)[1] == '.gds')
+    d2r = list(os.path.splitext(item)[0] for item in d2e)
+    try:
+        d3 = os.listdir(path + '/lef')
+    except:
+        d3 = []
+    d3e = list(item for item in d3 if os.path.splitext(item)[1] == '.lef')
+    d3r = list(os.path.splitext(item)[0] for item in d3e)
+    try:
+        d4 = os.listdir(path + '/mag')
+    except:
+        d4 = []
+    d4e = list(item for item in d4 if os.path.splitext(item)[1] == '.mag')
+    d4r = list(os.path.splitext(item)[0] for item in d4e)
+    try:
+        d5 = os.listdir(path + '/maglef')
+    except:
+        d5 = []
+    d5e = list(item for item in d5 if os.path.splitext(item)[1] == '.mag')
+    d5r = list(os.path.splitext(item)[0] for item in d5e)
+    try:
+        d6 = os.listdir(path + '/verilog')
+    except:
+        d6 = []
+    d6e = list(item for item in d6 if os.path.splitext(item)[1] == '.v')
+    d6r = list(os.path.splitext(os.path.splitext(item)[0])[0] for item in d6e)
+ 
+    d1r.sort()
+    d2r.sort()
+    d3r.sort()
+    d4r.sort()
+    d5r.sort()
+    d6r.sort()
+
+    d1_2 = list(item for item in d1r if item not in d2r)
+    d1_3 = list(item for item in d1r if item not in d3r)
+    d1_4 = list(item for item in d1r if item not in d4r)
+    d1_5 = list(item for item in d1r if item not in d5r)
+    d1_6 = list(item for item in d1r if item not in d6r)
+
+    d2_1 = list(item for item in d2r if item not in d1r)
+    d2_3 = list(item for item in d2r if item not in d3r)
+    d2_4 = list(item for item in d2r if item not in d4r)
+    d2_5 = list(item for item in d2r if item not in d5r)
+    d2_6 = list(item for item in d2r if item not in d6r)
+
+    d3_1 = list(item for item in d3r if item not in d1r)
+    d3_2 = list(item for item in d3r if item not in d2r)
+    d3_4 = list(item for item in d3r if item not in d4r)
+    d3_5 = list(item for item in d3r if item not in d5r)
+    d3_6 = list(item for item in d3r if item not in d6r)
+
+    d4_1 = list(item for item in d4r if item not in d1r)
+    d4_2 = list(item for item in d4r if item not in d2r)
+    d4_3 = list(item for item in d4r if item not in d3r)
+    d4_5 = list(item for item in d4r if item not in d5r)
+    d4_6 = list(item for item in d4r if item not in d6r)
+
+    d5_1 = list(item for item in d5r if item not in d1r)
+    d5_2 = list(item for item in d5r if item not in d2r)
+    d5_3 = list(item for item in d5r if item not in d3r)
+    d5_4 = list(item for item in d5r if item not in d4r)
+    d5_6 = list(item for item in d5r if item not in d6r)
+
+    d6_1 = list(item for item in d6r if item not in d1r)
+    d6_2 = list(item for item in d6r if item not in d2r)
+    d6_3 = list(item for item in d6r if item not in d3r)
+    d6_4 = list(item for item in d6r if item not in d4r)
+    d6_5 = list(item for item in d6r if item not in d5r)
+
+    d_complete = []
+    if do_cdl:
+        d_complete.extend(list(item for item in d1r if item not in d_complete))
+    if do_gds:
+        d_complete.extend(list(item for item in d2r if item not in d_complete))
+    if do_lef:
+        d_complete.extend(list(item for item in d3r if item not in d_complete))
+    if do_mag:
+        d_complete.extend(list(item for item in d4r if item not in d_complete))
+    if do_maglef:
+        d_complete.extend(list(item for item in d5r if item not in d_complete))
+    if do_verilog:
+        d_complete.extend(list(item for item in d6r if item not in d_complete))
+
+    d_all = d_complete
+    if do_cdl:
+        d_all = list(item for item in d_all if item in d1r)
+    if do_gds:
+        d_all = list(item for item in d_all if item in d2r)
+    if do_lef:
+        d_all = list(item for item in d_all if item in d3r)
+    if do_mag:
+        d_all = list(item for item in d_all if item in d4r)
+    if do_maglef:
+        d_all = list(item for item in d_all if item in d5r)
+    if do_verilog:
+        d_all = list(item for item in d_all if item in d6r)
+
+    d_notall = list(item for item in d_complete if item not in d_all)
+
+    d_all.sort()
+    d_complete.sort()
+    d_notall.sort()
+    
+    if debug:
+        print('Selected styles option: ' + ','.join(styles))
+        print('Selected formats option: ' + ','.join(formats))
+        print('\nd_complete = ' + ','.join(d_complete))
+        print('\nd_notall = ' + ','.join(d_notall) + '\n')
+
+    print('Library file type cross-correlation:' + '\n')
+
+    if 'allgood' in styles:
+        print('Cells appearing in all libraries:')
+        for cell in d_all.sort():
+           print(cell)
+
+    if 'cross' in styles:
+        # Print which cells appear in one format but not in another, for all format pairs
+        if do_cdl:
+            print('')
+            if do_gds and len(d1_2) > 0:
+                print('Cells appearing in cdl/ but not in gds/:')
+                for cell in d1_2:
+                    print(cell)
+            if do_lef and len(d1_3) > 0:
+                print('Cells appearing in cdl/ but not in lef/:')
+                for cell in d1_3:
+                    print(cell)
+            if do_mag and len(d1_4) > 0:
+                print('Cells appearing in cdl/ but not in mag/:')
+                for cell in d1_4:
+                    print(cell)
+            if do_maglef and len(d1_5) > 0:
+                print('Cells appearing in cdl/ but not in maglef/:')
+                for cell in d1_5:
+                    print(cell)
+            if do_verilog and len(d1_6) > 0:
+                print('Cells appearing in cdl/ but not in verilog/:')
+                for cell in d1_6:
+                    print(cell)
+
+        if do_gds:
+            print('')
+            if do_cdl and len(d2_1) > 0:
+                print('Cells appearing in gds/ but not in cdl/:')
+                for cell in d2_1:
+                    print(cell)
+            if do_lef and len(d2_3) > 0:
+                print('Cells appearing in gds/ but not in lef/:')
+                for cell in d2_3:
+                    print(cell)
+            if do_mag and len(d2_4) > 0:
+                print('Cells appearing in gds/ but not in mag/:')
+                for cell in d2_4:
+                    print(cell)
+            if do_maglef and len(d2_5) > 0:
+                print('Cells appearing in gds/ but not in maglef/:')
+                for cell in d2_5:
+                    print(cell)
+            if do_verilog and len(d2_6) > 0:
+                print('Cells appearing in gds/ but not in verilog/:')
+                for cell in d2_6:
+                    print(cell)
+
+        if do_lef:
+            print('')
+            if do_cdl and len(d3_1) > 0:
+                print('Cells appearing in lef/ but not in cdl/:')
+                for cell in d3_1:
+                    print(cell)
+            if do_gds and len(d3_2) > 0:
+                print('Cells appearing in lef/ but not in gds/:')
+                for cell in d3_2:
+                    print(cell)
+            if do_mag and len(d3_4) > 0:
+                print('Cells appearing in lef/ but not in mag/:')
+                for cell in d3_4:
+                    print(cell)
+            if do_maglef and len(d3_5) > 0:
+                print('Cells appearing in lef/ but not in maglef/:')
+                for cell in d3_5:
+                    print(cell)
+            if do_verilog and len(d3_6) > 0:
+                print('Cells appearing in lef/ but not in verilog/:')
+                for cell in d3_6:
+                    print(cell)
+
+        if do_mag:
+            print('')
+            if do_cdl and len(d4_1) > 0:
+                print('Cells appearing in mag/ but not in cdl/:')
+                for cell in d4_1:
+                    print(cell)
+            if do_gds and len(d4_2) > 0:
+                print('Cells appearing in mag/ but not in gds/:')
+                for cell in d4_2:
+                    print(cell)
+            if do_lef and len(d4_3) > 0:
+                print('Cells appearing in mag/ but not in lef/:')
+                for cell in d4_3:
+                    print(cell)
+            if do_maglef and len(d4_5) > 0:
+                print('Cells appearing in mag/ but not in maglef/:')
+                for cell in d4_5:
+                    print(cell)
+            if do_verilog and len(d4_6) > 0:
+                print('Cells appearing in mag/ but not in verilog/:')
+                for cell in d4_6:
+                    print(cell)
+
+        if do_maglef:
+            print('')
+            if do_cdl and len(d5_1) > 0:
+                print('Cells appearing in maglef/ but not in cdl/:')
+                for cell in d5_1:
+                    print(cell)
+            if do_gds and len(d5_2) > 0:
+                print('Cells appearing in maglef/ but not in gds/:')
+                for cell in d5_2:
+                    print(cell)
+            if do_lef and len(d5_3) > 0:
+                print('Cells appearing in maglef/ but not in lef/:')
+                for cell in d5_3:
+                    print(cell)
+            if do_mag and len(d5_4) > 0:
+                print('Cells appearing in maglef/ but not in mag/:')
+                for cell in d5_4:
+                    print(cell)
+            if do_verilog and len(d5_6) > 0:
+                print('Cells appearing in maglef/ but not in verilog/:')
+                for cell in d5_6:
+                    print(cell)
+        
+        if do_verilog:
+            print('')
+            if do_cdl and len(d6_1) > 0:
+                print('Cells appearing in verilog/ but not in cdl/:')
+                for cell in d6_1:
+                    print(cell)
+            if do_gds and len(d6_2) > 0:
+                print('Cells appearing in verilog/ but not in gds/:')
+                for cell in d6_2:
+                    print(cell)
+            if do_lef and len(d6_3) > 0:
+                print('Cells appearing in verilog/ but not in lef/:')
+                for cell in d6_3:
+                    print(cell)
+            if do_mag and len(d6_4) > 0:
+                print('Cells appearing in verilog/ but not in mag/:')
+                for cell in d6_4:
+                    print(cell)
+            if do_maglef and len(d6_5) > 0:
+                print('Cells appearing in verilog/ but not in maglef/:')
+                for cell in d6_5:
+                    print(cell)
+
+    if 'cell' in styles:
+        # Print one cell per row, with list of formats per cell
+        for cell in d_complete:
+            informats = []
+            if do_cdl and cell in d1r:
+                informats.append('CDL')
+            if do_gds and cell in d2r:
+                informats.append('GDS')
+            if do_lef and cell in d3r:
+                informats.append('LEF')
+            if do_mag and cell in d4r:
+                informats.append('mag')
+            if do_maglef and cell in d5r:
+                informats.append('maglef')
+            if do_verilog and cell in d6r:
+                informats.append('verilog')
+            print(cell + ': ' + ','.join(informats))
+
+    if 'notcell' in styles:
+        # Print one cell per row, with list of missing formats per cell
+        for cell in d_complete:
+            informats = []
+            if do_cdl and cell not in d1r:
+                informats.append('CDL')
+            if do_gds and cell not in d2r:
+                informats.append('GDS')
+            if do_lef and cell not in d3r:
+                informats.append('LEF')
+            if do_mag and cell not in d4r:
+                informats.append('mag')
+            if do_maglef and cell not in d5r:
+                informats.append('maglef')
+            if do_verilog and cell not in d6r:
+                informats.append('verilog')
+            print(cell + ': ' + ','.join(informats))
+
+    if 'table' in styles:
+        cellnamelen = 0
+        for cell in d_complete:
+            if len(cell) > cellnamelen:
+                cellnamelen = len(cell)
+
+        # Print one cell per row, with list of formats per cell in tabular form
+        outline = 'cell'
+        outline += ' ' * (cellnamelen - 5)
+        fmtspc = 0
+        if do_cdl:
+            outline += ' CDL'
+            fmtspc += 4
+        if do_gds:
+            outline += ' GDS'
+            fmtspc += 4
+        if do_lef:
+            outline += ' LEF'
+            fmtspc += 4
+        if do_mag:
+            outline += ' mag'
+            fmtspc += 4
+        if do_maglef:
+            outline += ' maglef'
+            fmtspc += 7
+        if do_verilog:
+            outline += ' verilog'
+            fmtspc += 8
+        print(outline)
+        print('-' * (cellnamelen + fmtspc))
+        for cell in d_complete:
+            informats = []
+            outline = cell
+            outline += ' ' * (cellnamelen - len(cell))
+            if do_cdl:
+                if cell in d1r:
+                    outline += ' X  '
+                else:
+                    outline += '    '
+            if do_gds:
+                if cell in d2r:
+                    outline += ' X  '
+                else:
+                    outline += '    '
+            if do_lef:
+                if cell in d3r:
+                    outline += ' X  '
+                else:
+                    outline += '    '
+            if do_mag:
+                if cell in d4r:
+                    outline += ' X  '
+                else:
+                    outline += '    '
+            if do_maglef:
+                if cell in d5r:
+                    outline += ' X     '
+                else:
+                    outline += '       '
+            if do_verilog:
+                if cell in d6r:
+                    outline += ' X'
+                else:
+                    outline += '  '
+            print(outline)
+        print('-' * (cellnamelen + fmtspc))
+
+def usage():
+    print('compare_dirs.py <path_to_dir> [-styles=<style_list>] [-debug] [-formats=<format_list>|"all"]')
+    print('    <format_list>:  Comma-separated list of one or more of the following formats:')
+    print('             cdl, gds, lef, verilog, mag, maglef')
+    print('    <style_list>: Comma-separated list of one or more of the following styles:')
+    print('             allgood, cross, cell, notcell, table')
+    return 0
+
+if __name__ == '__main__':
+
+    options = []
+    arguments = []
+    for item in sys.argv[1:]:
+        if item.find('-', 0) == 0:
+            options.append(item)
+        else:
+            arguments.append(item)
+
+    if len(arguments) < 1:
+        print("Not enough options given to compare_dirs.py.")
+        usage()
+        sys.exit(0)
+
+    debug = True if '-debug' in options else False
+
+    allformats = ['cdl', 'gds', 'lef', 'mag', 'maglef', 'verilog']
+    allstyles = ['allgood', 'cross', 'cell', 'notcell', 'table']
+
+    formats = allformats
+    styles = ['table']
+
+    for option in options:
+        if '=' in option:
+            optpair = option.split('=')
+            if optpair[0] == '-styles' or optpair[0] == '-style':
+                if optpair[1] == 'all':
+                    styles = allstyles
+                else:
+                    styles = optpair[1].split(',')
+            elif optpair[0] == '-formats' or optpair[0] == '-format':
+                if optpair[1] == 'all':
+                    formats = allformats
+                else:
+                    formats = optpair[1].split(',')
+
+    path = arguments[0]
+    compare_dirs(path, styles, formats, debug)
+    sys.exit(0)