diff --git a/lib/scripts/fig2pdftex.py b/lib/scripts/fig2pdftex.py
index b458ccd8f3..10e9c5a89d 100644
--- a/lib/scripts/fig2pdftex.py
+++ b/lib/scripts/fig2pdftex.py
@@ -78,7 +78,7 @@ else:
     # with tetex.
     epsfile = outbase + '.pstex'
     tmp = mkstemp()
-    boundingboxline = re.compile(b'%%BoundingBox:\s+(\d*)\s+(\d*)\s+(\d*)\s+(\d*)')
+    boundingboxline = re.compile(br'%%BoundingBox:\s+(\d*)\s+(\d*)\s+(\d*)\s+(\d*)')
     for line in open(epsfile, 'rb'):
         if line[:13] == b'%%BoundingBox':
             (llx, lly, urx, ury) = list(map(int, boundingboxline.search(line).groups()))
diff --git a/lib/scripts/layout2layout.py b/lib/scripts/layout2layout.py
index 88ada1213e..c2fc7c20a7 100644
--- a/lib/scripts/layout2layout.py
+++ b/lib/scripts/layout2layout.py
@@ -457,10 +457,10 @@ def convert(lines, end_format):
     re_ChapterStyle = re.compile(b'^\\s*Style\\s+Chapter\\s*$', re.IGNORECASE)
     re_InsetLayout_CaptionLTNN = re.compile(b'^(\\s*InsetLayout\\s+)(Caption:LongTableNonumber)', re.IGNORECASE)
     # for format 64
-    re_trimLabelString = re.compile(b'^(\\s*LabelString\s+)"\\s*(.*?)\\s*"\\s*$')
-    re_trimLabelStringAppendix  = re.compile(b'^(\\s*LabelStringAppendix\s+)"\\s*(.*?)\\s*"\\s*$')
-    re_trimEndLabelString = re.compile(b'^(\\s*EndLabelString\s+)"\\s*(.*?)\\s*"\\s*$')
-    re_trimLabelCounter = re.compile(b'^(\\s*LabelCounter\s+)"\\s*(.*?)\\s*"\\s*$')
+    re_trimLabelString = re.compile(b'^(\\s*LabelString\\s+)"\\s*(.*?)\\s*"\\s*$')
+    re_trimLabelStringAppendix  = re.compile(b'^(\\s*LabelStringAppendix\\s+)"\\s*(.*?)\\s*"\\s*$')
+    re_trimEndLabelString = re.compile(b'^(\\s*EndLabelString\\s+)"\\s*(.*?)\\s*"\\s*$')
+    re_trimLabelCounter = re.compile(b'^(\\s*LabelCounter\\s+)"\\s*(.*?)\\s*"\\s*$')
 
 
     # counters for sectioning styles (hardcoded in 1.3)
diff --git a/lib/scripts/legacy_lyxpreview2ppm.py b/lib/scripts/legacy_lyxpreview2ppm.py
index 8effd5bd00..29eb833f54 100644
--- a/lib/scripts/legacy_lyxpreview2ppm.py
+++ b/lib/scripts/legacy_lyxpreview2ppm.py
@@ -156,7 +156,7 @@ def legacy_extract_metrics_info(log_file):
 def extract_resolution(log_file, dpi):
     fontsize_re = re.compile(b"Preview: Fontsize")
     magnification_re = re.compile(b"Preview: Magnification")
-    extract_decimal_re = re.compile(b"([0-9\.]+)")
+    extract_decimal_re = re.compile(br"([0-9\.]+)")
     extract_integer_re = re.compile(b"([0-9]+)")
 
     found_fontsize = 0
diff --git a/lib/scripts/lyxpak.py b/lib/scripts/lyxpak.py
index 2aaf2db42b..affef65644 100755
--- a/lib/scripts/lyxpak.py
+++ b/lib/scripts/lyxpak.py
@@ -37,7 +37,7 @@ if running_on_windows:
     from tempfile import NamedTemporaryFile
 
 # Pre-compiled regular expressions.
-re_lyxfile = re.compile(b"\.lyx$")
+re_lyxfile = re.compile(br"\.lyx$")
 re_input = re.compile(b'^(.*)\\\\(input|include){(\\s*)(.+)(\\s*)}.*$')
 re_ertinput = re.compile(b'^(input|include)({)(\\s*)(.+)(\\s*)}.*$')
 re_package = re.compile(b'^(.*)\\\\(usepackage){(\\s*)(.+)(\\s*)}.*$')
diff --git a/lib/scripts/lyxpaperview.py b/lib/scripts/lyxpaperview.py
index 09256da7cb..a0f2bedfe1 100755
--- a/lib/scripts/lyxpaperview.py
+++ b/lib/scripts/lyxpaperview.py
@@ -78,7 +78,7 @@ def find(args, path):
         # use locate if possible (faster)
         if find_exe(['locate']):
             p1 = subprocess.Popen(['locate', '-i', args[0].lower()], stdout=subprocess.PIPE)
-            px = subprocess.Popen(['grep', '-Ei', '\.pdf$|\.ps$'], stdin=p1.stdout, stdout=subprocess.PIPE)
+            px = subprocess.Popen(['grep', '-Ei', r'\.pdf$|\.ps$'], stdin=p1.stdout, stdout=subprocess.PIPE)
             for arg in args:
                if arg == args[0]:
                    # have this already
diff --git a/lib/scripts/lyxpreview2bitmap.py b/lib/scripts/lyxpreview2bitmap.py
index eee000deea..719738d002 100755
--- a/lib/scripts/lyxpreview2bitmap.py
+++ b/lib/scripts/lyxpreview2bitmap.py
@@ -120,7 +120,7 @@ def extract_metrics_info(dvipng_stdout):
     # "\[[0-9]+" can match two kinds of numbers: page numbers from dvipng
     # and glyph numbers from mktexpk. The glyph numbers always match
     # "\[[0-9]+\]" while the page number never is followed by "\]". Thus:
-    page_re = re.compile("\[([0-9]+)[^]]");
+    page_re = re.compile(r"\[([0-9]+)[^]]");
     metrics_re = re.compile("depth=(-?[0-9]+) height=(-?[0-9]+)")
 
     success = 0
@@ -197,7 +197,7 @@ def fix_latex_file(latex_file, pdf_output):
 
 
 def convert_to_ppm_format(pngtopnm, basename):
-    png_file_re = re.compile("\.png$")
+    png_file_re = re.compile(r"\.png$")
 
     for png_file in glob.glob("%s*.png" % basename):
         ppm_file = png_file_re.sub(".ppm", png_file)
diff --git a/lib/scripts/lyxpreview_tools.py b/lib/scripts/lyxpreview_tools.py
index 7783fe2b7d..cca359e7c4 100644
--- a/lib/scripts/lyxpreview_tools.py
+++ b/lib/scripts/lyxpreview_tools.py
@@ -1,4 +1,3 @@
-
 # file lyxpreview_tools.py
 # This file is part of LyX, the document processor.
 # Licence details can be found in the file COPYING.
diff --git a/lib/scripts/prefs2prefs_prefs.py b/lib/scripts/prefs2prefs_prefs.py
index 08c1f386b5..78870a3402 100644
--- a/lib/scripts/prefs2prefs_prefs.py
+++ b/lib/scripts/prefs2prefs_prefs.py
@@ -223,7 +223,7 @@ def remove_obsolete(line):
 
 
 def language_use_babel(line):
-	if not line.lower().startswith("\language_use_babel"):
+	if not line.lower().startswith(r"\language_use_babel"):
 		return no_match
 	re_lub = re.compile(r'^\\language_use_babel\s+"?(true|false)', re.IGNORECASE)
 	m = re_lub.match(line)
@@ -364,7 +364,7 @@ def split_pdf_format(line):
 				viewer = ''
 			else:
 				viewer = entries[5]
-			converted = line.replace('application/pdf', '') + '''
+			converted = line.replace('application/pdf', '') + r'''
 \Format pdf6       pdf    "PDF (graphics)"        "" "''' + viewer + '"	""	"vector"	"application/pdf"'
 			return (True, converted)
 	elif line.lower().startswith("\\viewer_alternatives") or \