diff -r 57b995de80b5 -r 06221010c81d cmd.rst
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+++ b/cmd.rst	Sun Aug 21 22:25:21 2011 +0300
@@ -0,0 +1,123 @@
+.. -*- coding: utf-8; -*-
+
+====================
+ CMD Windows shell.
+====================
+.. contents::
+
+Quoting.
+========
+
+ * Arguments are delimited by white space, which is either a space or a tab.
+ * A string surrounded by double quotation marks is interpreted as a single
+   argument.
+ * A double quotation mark preceded by a backslash, \", is interpreted as a
+   literal double quotation mark.
+ * Backslashes are interpreted literally, unless they immediately precede a
+   double quotation mark.
+ * If an even number of backslashes is followed by a double quotation mark,
+   then one backslash (\) is placed in the argv array for every pair of
+   backslashes (\\), and the double quotation mark (") is interpreted as a
+   string delimiter.
+ * If an odd number of backslashes is followed by a double quotation mark,
+   then one backslash (\) is placed in the argv array for every pair of
+   backslashes (\\) and the double quotation mark is interpreted as an escape
+   sequence by the remaining backslash, causing a literal double quotation
+   mark (") to be placed in argv.
+ * In double quote mark need surround such chars::
+
+     & < > [ ] { } ^ = ; ! ' + , ` ~ %
+
+   Also all this char can be escaped by ^ char.
+ * Long line can be truncated by ^ char, in this case trailing white spaces
+   not allowed.
+ * To quote percent sign % before alpha char in batch file double it
+   occurrences or plase in quotes::
+
+     prog '%'HOME'%' "%"HOME"%" %%HOME%
+
+  http://msdn.microsoft.com/en-us/library/ms880421.aspx
+                Parsing C Command-Line Arguments
+
+Variables.
+==========
+
+Variable name start with letter and underscore, next chars can be letter,
+number and underscore. Variable name is case insensitive.
+
+List of variables.
+------------------
+::
+
+  cmd> set
+  ...
+  VAR=VALUE
+
+Getting.
+--------
+
+Write %VAR% in place where you want insert variable VAr value.
+
+Setting.
+--------
+::
+
+  cmd> set /p VAR=VALUE
+
+Deleting.
+---------
+::
+
+  cmd> set VAR=
+
+Input from user.
+----------------
+::
+
+  cmd> set /p VAR=PROMPT
+
+VAR is variable name, PROMPT is displayed prompt.
+
+Input from file.
+----------------
+
+  cmd> set /p VAR=<FILE
+
+VAR is variable name, FILE is file name. Sfter executing VAR contain first
+line from FILE.
+
+CMD tricks.
+===========
+::
+
+  $ set /p TOOLOUTPUT= < temp.txt
+
+  $ for /f "tokens=*" %%i in ('%~dp0sometool.exe') do set TOOLOUTPUT=%%i
+
+  $ for /f "tokens=1 delims=" %%s in (users.txt) do (echo %%S & command "%%S") >> outputfile.txt
+
+Limits.
+=======
+
+Variable value and one line command string after expansion can not exceed 8191
+characters for Windows XP and later and 2047 for Windows NT, Windows 2000.
+
+  http://support.microsoft.com/default.aspx?scid=kb;en-us;830473
+                Command prompt (Cmd. exe) command-line string limitation
+
+How run cmd on 64-bit OS.
+=========================
+
+From 64-bit process::
+
+  %windir%\System32\cmd.exe (for 64-bit)
+  %windir%\SysWOW64\cmd.exe (for 32-bit)
+
+From 32-bit process::
+
+  %windir%\System32\cmd.exe (for 32-bit)
+  %windir%\Sysnative\cmd.exe (for 64-bit)
+
+  http://msdn.microsoft.com/en-us/library/aa384187%28VS.85%29.aspx
+                File System Redirector
+