minor, use sys.exit print shorthand

diff --git a/src/gen-arabic-table.py b/src/gen-arabic-table.py
index f910d41..e4a4ddf 100755
--- a/src/gen-arabic-table.py
+++ b/src/gen-arabic-table.py

@@ -11,8 +11,7 @@
 import io, os.path, sys
 
 if len (sys.argv) != 4:
-	print (__doc__, file=sys.stderr)
-	sys.exit (1)
+	sys.exit (__doc__)
 
 files = [io.open (x, encoding='utf-8') for x in sys.argv[1:]]
 

diff --git a/src/gen-emoji-table.py b/src/gen-emoji-table.py
index 6d5ca6e..5b78bd3 100755
--- a/src/gen-emoji-table.py
+++ b/src/gen-emoji-table.py

@@ -12,8 +12,7 @@
 import packTab
 
 if len (sys.argv) != 2:
-	print(__doc__, file=sys.stderr)
-	sys.exit (1)
+	sys.exit (__doc__)
 
 f = open(sys.argv[1])
 header = [f.readline () for _ in range(10)]

diff --git a/src/gen-harfbuzzcc.py b/src/gen-harfbuzzcc.py
index c0ac7d7..b4f24af 100755
--- a/src/gen-harfbuzzcc.py
+++ b/src/gen-harfbuzzcc.py

@@ -5,7 +5,7 @@
 import io, os, re, sys
 
 if len (sys.argv) < 3:
-	sys.exit(__doc__)
+	sys.exit (__doc__)
 
 output_file = sys.argv[1]
 source_paths = sys.argv[2:]

diff --git a/src/gen-indic-table.py b/src/gen-indic-table.py
index edc898b..c45e99b 100755
--- a/src/gen-indic-table.py
+++ b/src/gen-indic-table.py

@@ -11,8 +11,7 @@
 import io, sys
 
 if len (sys.argv) != 4:
-	print (__doc__, file=sys.stderr)
-	sys.exit (1)
+	sys.exit (__doc__)
 
 ALLOWED_SINGLES = [0x00A0, 0x25CC]
 ALLOWED_BLOCKS = [

diff --git a/src/gen-tag-table.py b/src/gen-tag-table.py
index 41baff3..e78389c 100755
--- a/src/gen-tag-table.py
+++ b/src/gen-tag-table.py

@@ -36,8 +36,7 @@
 import unicodedata
 
 if len (sys.argv) != 3:
-	print (__doc__, file=sys.stderr)
-	sys.exit (1)
+	sys.exit (__doc__)
 
 from html import unescape
 def html_unescape (parser, entity):

diff --git a/src/gen-ucd-table.py b/src/gen-ucd-table.py
index 02c7ebd..6612250 100755
--- a/src/gen-ucd-table.py
+++ b/src/gen-ucd-table.py

@@ -11,8 +11,7 @@
 logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.INFO)
 
 if len (sys.argv) not in (2, 3):
-	print(__doc__, file=sys.stderr)
-	sys.exit(1)
+	sys.exit (__doc__)
 
 # https://github.com/harfbuzz/packtab
 import packTab

diff --git a/src/gen-use-table.py b/src/gen-use-table.py
index 26eb0a5..4845c19 100755
--- a/src/gen-use-table.py
+++ b/src/gen-use-table.py

@@ -14,8 +14,7 @@
 import sys
 
 if len (sys.argv) != 5:
-	print (__doc__, file=sys.stderr)
-	sys.exit (1)
+	sys.exit (__doc__)
 
 BLACKLISTED_BLOCKS = ["Thai", "Lao"]
 

diff --git a/src/gen-vowel-constraints.py b/src/gen-vowel-constraints.py
index e758ea0..4e17173 100755
--- a/src/gen-vowel-constraints.py
+++ b/src/gen-vowel-constraints.py

@@ -23,8 +23,7 @@
 import sys
 
 if len (sys.argv) != 3:
-	print (__doc__, file=sys.stderr)
-	sys.exit (1)
+	sys.exit (__doc__)
 
 with io.open (sys.argv[2], encoding='utf-8') as f:
 	scripts_header = [f.readline () for i in range (2)]