Merged revisions 79822,79828,79862,80067,80069,80080-80081,80084,80432-80433 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r79822 | georg.brandl | 2010-04-06 08:18:15 +0000 (Di, 06 Apr 2010) | 1 line

  #8320: document return value of recv_into().
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  r79828 | georg.brandl | 2010-04-06 14:33:44 +0000 (Di, 06 Apr 2010) | 1 line

  Add JP.
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  r79862 | georg.brandl | 2010-04-06 20:27:59 +0000 (Di, 06 Apr 2010) | 1 line

  Fix syntax.
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  r80067 | georg.brandl | 2010-04-14 08:53:38 +0000 (Mi, 14 Apr 2010) | 1 line

  #5341: typo.
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  r80069 | georg.brandl | 2010-04-14 13:50:31 +0000 (Mi, 14 Apr 2010) | 1 line

  Add an x-ref to where the O_ constants are documented and move the SEEK_ constants after lseek().
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  r80080 | georg.brandl | 2010-04-14 19:16:38 +0000 (Mi, 14 Apr 2010) | 1 line

  #8399: add note about Windows and O_BINARY.
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  r80081 | georg.brandl | 2010-04-14 21:34:44 +0000 (Mi, 14 Apr 2010) | 1 line

  #5250: document __instancecheck__ and __subclasscheck__.  I hope the part about the class/metaclass distinction is understandable.
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  r80084 | georg.brandl | 2010-04-14 21:46:45 +0000 (Mi, 14 Apr 2010) | 1 line

  Fix missing.
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  r80432 | georg.brandl | 2010-04-24 08:56:58 +0000 (Sa, 24 Apr 2010) | 1 line

  Markup fixes.
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  r80433 | georg.brandl | 2010-04-24 09:08:10 +0000 (Sa, 24 Apr 2010) | 1 line

  #7507: quote "!" in pipes.quote(); it is a special character for some shells.
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diff --git a/Lib/pipes.py b/Lib/pipes.py
index 25e9915..02e1257 100644
--- a/Lib/pipes.py
+++ b/Lib/pipes.py
@@ -263,11 +263,11 @@
 
 # Reliably quote a string as a single argument for /bin/sh
 
-_safechars = string.ascii_letters + string.digits + '!@%_-+=:,./' # Safe unquoted
-_funnychars = '"`$\\'                           # Unsafe inside "double quotes"
+# Safe unquoted
+_safechars = frozenset(string.ascii_letters + string.digits + '@%_-+=:,./')
 
 def quote(file):
-    ''' return a shell-escaped version of the file string '''
+    """Return a shell-escaped version of the file string."""
     for c in file:
         if c not in _safechars:
             break
@@ -275,11 +275,6 @@
         if not file:
             return "''"
         return file
-    if '\'' not in file:
-        return '\'' + file + '\''
-    res = ''
-    for c in file:
-        if c in _funnychars:
-            c = '\\' + c
-        res = res + c
-    return '"' + res + '"'
+    # use single quotes, and put single quotes into double quotes
+    # the string $'b is then quoted as '$'"'"'b'
+    return "'" + file.replace("'", "'\"'\"'") + "'"