498 lines
20 KiB
Plaintext
498 lines
20 KiB
Plaintext
<sect1 id="setup-env"><title>Environment Variables</title>
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<para>
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You may wish to specify settings of several important environment
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variables that affect Cygwin's operation. Some of these settings need
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to be in effect prior to launching the initial Cygwin session (before
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starting your bash shell, for instance), and are, consequentially, best
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placed in a .bat file. An initial file is named Cygwin.bat and is created
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in the Cygwin root directory that you specified during setup. Note that
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the "Cygwin" option of the Start Menu points to Cygwin.bat. Edit
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Cygwin.bat to your liking or create your own .bat files to start
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Cygwin processes.</para>
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<para>
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The <envar>CYGWIN</envar> variable is used to configure many global
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settings for the Cygwin runtime system. Initially you can leave
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<envar>CYGWIN</envar> unset or set it to <literal>tty</literal> (e.g.
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to support job control with ^Z etc...) using a syntax like this in the
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DOS shell, before launching bash.</para>
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<screen>
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<prompt>C:\></prompt> <userinput>set CYGWIN=tty notitle glob</userinput>
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</screen>
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<para>
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Locale support is controlled by the <envar>LANG</envar> and
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<envar>LC_xxx</envar> environment variables. You can set all of them
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but Cygwin itself only honors the variables <envar>LC_ALL</envar>,
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<envar>LC_CTYPE</envar>, and <envar>LANG</envar>, in this order, according
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to the POSIX standard. The first one found rules. For a more detailed
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description see <xref linkend="setup-locale"></xref>.
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</para>
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<para>
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The <envar>PATH</envar> environment variable is used by Cygwin
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applications as a list of directories to search for executable files
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to run. This environment variable is converted from Windows format
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(e.g. <filename>C:\Windows\system32;C:\Windows</filename>) to UNIX format
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(e.g., <filename>/cygdrive/c/Windows/system32:/cygdrive/c/Windows</filename>)
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when a Cygwin process first starts.
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Set it so that it contains at least the <filename>x:\cygwin\bin</filename>
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directory where "<filename>x:\cygwin</filename> is the "root" of your
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cygwin installation if you wish to use cygwin tools outside of bash.
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This is usually done by the batch file you're starting your shell with.
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</para>
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<para>
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The <envar>HOME</envar> environment variable is used by many programs to
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determine the location of your home directory and we recommend that it be
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defined. This environment variable is also converted from Windows format
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when a Cygwin process first starts. It's usually set in the shell
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profile scripts in the /etc directory.
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</para>
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<para>
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The <envar>TERM</envar> environment variable specifies your terminal
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type. It is automatically set to <literal>cygwin</literal> if you have
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not set it to something else.
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</para>
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<para>The <envar>LD_LIBRARY_PATH</envar> environment variable is used by
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the Cygwin function <function>dlopen ()</function> as a list of
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directories to search for .dll files to load. This environment variable
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is converted from Windows format to UNIX format when a Cygwin process
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first starts. Most Cygwin applications do not make use of the
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<function>dlopen ()</function> call and do not need this variable.
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</para>
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</sect1>
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<sect1 id="setup-maxmem"><title>Changing Cygwin's Maximum Memory</title>
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<para>
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Cygwin's heap is extensible. However, it does start out at a fixed size
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and attempts to extend it may run into memory which has been previously
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allocated by Windows. In some cases, this problem can be solved by
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adding an entry in the either the <literal>HKEY_LOCAL_MACHINE</literal>
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(to change the limit for all users) or
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<literal>HKEY_CURRENT_USER</literal> (for just the current user) section
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of the registry. </para>
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<para>
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Add the <literal>DWORD</literal> value <literal>heap_chunk_in_mb</literal>
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and set it to the desired memory limit in decimal MB. It is preferred to do
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this in Cygwin using the <command>regtool</command> program included in the
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Cygwin package.
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(For more information about <command>regtool</command> or the other Cygwin
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utilities, see <xref linkend="using-utils"></xref> or use the
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<literal>--help</literal> option of each util.) You should always be careful
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when using <command>regtool</command> since damaging your system registry can
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result in an unusable system. This example sets memory limit to 1024 MB:
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<screen>
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regtool -i set /HKLM/Software/Cygwin/heap_chunk_in_mb 1024
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regtool -v list /HKLM/Software/Cygwin
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</screen>
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</para>
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<para>
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Exit all running Cygwin processes and restart them. Memory can be allocated up
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to the size of the system swap space minus any the size of any running
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processes. The system swap should be at least as large as the physically
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installed RAM and can be modified under the System category of the
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Control Panel.
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</para>
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<para>
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Here is a small program written by DJ Delorie that tests the
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memory allocation limit on your system:
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<screen>
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main()
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{
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unsigned int bit=0x40000000, sum=0;
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char *x;
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while (bit > 4096)
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{
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x = malloc(bit);
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if (x)
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sum += bit;
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bit >>= 1;
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}
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printf("%08x bytes (%.1fMb)\n", sum, sum/1024.0/1024.0);
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return 0;
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}
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</screen>
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You can compile this program using:
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<screen>
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gcc max_memory.c -o max_memory.exe
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</screen>
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Run the program and it will output the maximum amount of allocatable memory.
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</para>
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</sect1>
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<sect1 id="setup-locale"><title>Internationalization</title>
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<sect2 id="setup-locale-ov"><title>Overview</title>
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<para>
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Internationalization support is controlled by the <envar>LANG</envar> and
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<envar>LC_xxx</envar> environment variables. You can set all of them
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but Cygwin itself only honors the variables <envar>LC_ALL</envar>,
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<envar>LC_CTYPE</envar>, and <envar>LANG</envar>, in this order, according
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to the POSIX standard. The content of these variables should follow the
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POSIX standard for a locale specifier. The correct form of a locale
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specifier is</para>
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<screen>
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language[[_TERRITORY][.charset][@modifier]]
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</screen>
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<para>"language" is a lowercase two character string per ISO 639-1,
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"TERRITORY" is an uppercase two character string per ISO 3166, charset is
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one of a list of supported character sets, and the modifier doesn't matter
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here (though it might for some applications). If you're interested in the
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exact description, you can find it in the online publication of the POSIX
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manual pages on the homepage of the
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<ulink url="http://www.opengroup.org/">Open Group</ulink>.</para>
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<para>Typical locale specifiers are</para>
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<screen>
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"de_CH" language = German, territory = Switzerland, default charset
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"fr_FR.UTF-8" language = french, territory = France, charset = UTF-8
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"ko_KR.eucKR" language = korean, territory = South Korea, charset = eucKR
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</screen>
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<para>
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And let's not forget the default locale called "C" or "POSIX"
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which basically only supports plain ASCII code. If the aforementioned
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environment variables are not set, or set to "C" or "POSIX", you get the
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default ASCII-only behaviour.
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</para>
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<para>
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Right now the language and territory content is not evaluated by Cygwin any
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further. The only important part so far is the character set. How does that
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work?
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</para>
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</sect2>
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<sect2 id="setup-locale-how"><title>How to set the locale</title>
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<itemizedlist mark="bullet">
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<listitem><para>
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The default locale is the "C" or "POSIX" locale. In this locale, basically
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only ASCII characters are supported. Even if one of the aforementioned
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environment variables are set to something else, it's the application's
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responsibility to call the function <function>setlocale</function>,
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typically like this</para>
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<screen>
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setlocale (LC_ALL, "");
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</screen>
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<para>to switch to another locale according to the settings of the
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internationalization environment variables.
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</para></listitem>
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<listitem><para>
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Assume that you've set one of the aforementioned environment variables to some
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valid POSIX locale value, other than "C" and "POSIX", and assume that you
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call an application which calls <function>setlocale</function> as above.</para>
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<para>Assume further that you're living in Japan. You might want to use
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the language code "ja" and the territory "JP", thus setting, say,
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<envar>LANG</envar> to "ja_JP". You didn't set a character set, so
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what will Cygwin use now? Easy! It will use the default Windows ANSI
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codepage of your system, if it's supported by Cygwin. Hopefully Cygwin
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supports all relevant default ANSI codepages...</para>
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<note><para>For a list of supported character sets, see
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<xref linkend="setup-locale-charsetlist"></xref>
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</para></note>
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</listitem>
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<listitem><para>
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You don't want to use the default Windows codepage as character set?
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In that case you have to specify the charset explicitely. For instance,
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assume you're from Italy and don't want to use the default Windows codepage
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1252, but the more portable ISO-8859-15 character set. What you can do is
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to set the <envar>LANG</envar> variable in the
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<filename>C:\cygwin\Cygwin.bat</filename> file which is the batch file
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to start a Cygwin session from the "Cygwin" desktop shortcut.</para>
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<screen>
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@echo off
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C:
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chdir C:\cygwin\bin
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set LANG=it_IT.ISO-8859-15
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bash --login -i
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</screen>
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</listitem>
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<listitem><para>
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Most singlebyte or doublebyte charsets have a disadvantage. Windows
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filesystems use the Unicode character set in the UTF-16 encoding to store filename information. Not all characters
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from the Unicode character set are available in a singlebyte or doublebyte
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charset. While Cygwin has a workaround to access files with unusual
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characters (see <xref linkend="pathnames-unusual"></xref>), a better
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workaround is to use always the UTF-8 character set. UTF-8 is the only
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multibyte character set which can represent <emphasis>every</emphasis>
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Unicode character.</para>
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<screen>
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set LANG=es_MX.UTF-8
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</screen>
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<para>For a description of the Unicode standard, see the homepage of the
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<ulink url="http://www.unicode.org/">Unicode Consortium</ulink>.
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</para></listitem>
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</itemizedlist>
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</sect2>
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<sect2 id="setup-locale-problems"><title>Potential Problems</title>
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<para>
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You can set the above internationalization variables not only in
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<filename>Cygwin.bat</filename> or in the Windows environment, but also
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in your Cygwin shell on the fly, even switch to yet another character
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set, and yet another. In bash for instance:</para>
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<screen>
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<prompt>bash$</prompt> export LC_CTYPE="nl_BE.UTF-8"
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</screen>
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<para>However, here's a problem. At the start of the first Cygwin process
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in a session, the Windows environment has to be converted from UTF-16 to
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some singlebyte or multibyte charset. If the internationalization environment
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variable hasn't been set <emphasis>before</emphasis> starting this process,
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Cygwin has to make an educated guess which charset to use to convert
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the environment itself. The only reproducible way to do that in the absence
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of <envar>LC_ALL</envar>, <envar>LC_CTYPE</envar>, or <envar>LANG</envar>,
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is to use the current Windows ANSI codepage.</para>
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<para>As long as the environment only contains ASCII characters, this is
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no problem. But if it contains native characters, and you're planning
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to use, say, UTF-8, the environment will result in invalid characters in
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the UTF-8 charset. This would be especially a problem in variables like
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<envar>PATH</envar>.</para>
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<note><para>Per POSIX, the name of an environment variable should only
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consist of valid ASCII characters, and only of uppercase letters, digits, and
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the underscore for maximum portablilty.</para></note>
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<para>Symbolic links, too, may pose a problem when switching charsets on
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the fly. A symbolic link contains the filename of the target file the
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symlink points to. When a symlink had been created with older versions
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of Cygwin, the current ANSI or OEM character set had been used to store
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the target filename, dependent on the old <envar>CYGWIN</envar>
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environment variable setting <envar>codepage</envar> (see <xref
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linkend="cygwinenv-removed-options"></xref>. If the target filename
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contains non-ASCII characters and you use another character set than
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your default ANSI/OEM charset, the target filename of the symlink is now
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potentially an invalid character sequence in the new character set.
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This behaviour is not different from the behaviour in other Operating
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Systems. So, if you suddenly can't access a symlink anymore which
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worked all these years before, maybe it's because you switched to
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another character set. This doesn't occur with symlinks created with
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Cygwin 1.7 or later. </para>
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</sect2>
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<sect2 id="setup-locale-missing"><title>What does not work?</title>
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<para>
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Except for <envar>LC_ALL</envar>, <envar>LC_CTYPE</envar>,
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and <envar>LANG</envar>, all other LC_xxx environment variables,
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<envar>LC_COLLATE</envar>, <envar>LC_MESSAGES</envar>,
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<envar>LC_MONETARY</envar>, <envar>LC_NUMERIC</envar>,
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and <envar>LC_TIME</envar>, are ignored right now. This means, while Cygwin
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supports different character sets, it does <emphasis>not</emphasis> support
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real localization so far. There's no support for locale-specific monetary
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symbols, for a decimalpoint other than '.', no support for native time
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formats, and no support for native language sorting orders.
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</para>
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<para>Cygwin's internationalization support is work in progress and we would
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be glad for coding help in this area.</para>
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</sect2>
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<sect2 id="setup-locale-charsetlist"><title>List of supported character sets</title>
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<para>Last but not least, here's the list of currently supported character
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sets. The left-hand expression is the name of the charset, as you would use
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it in the internationalization environment variables as outlined above.
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</para>
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<para>The right-hand side is the number of the equivalent Windows
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codepage as well as the Windows name of the codepage. They are only
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noted here for reference. Don't try to use the bare codepage number or
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the Windows name of the codepage as charset in locale specifiers, unless
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they happen to be identical with the left-hand side. Especially in case
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oif the "CPxxx" style charsets, always use them with the trailing "CP".</para>
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<para>This works:</para>
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<screen>
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set LC_ALL=en_US.CP437
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</screen>
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<para>This does <emphasis>not</emphasis> work:</para>
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<screen>
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set LC_ALL=en_US.437
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</screen>
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<para>You can find a full list of Windows codepages on the Microsoft MSDN page
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<ulink url="http://msdn.microsoft.com/en-us/library/dd317756(VS.85).aspx">Code Page Identifiers</ulink>.</para>
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<screen>
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Charset Codepage
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CP437 437 (OEM United States)
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CP720 720 (DOS Arabic)
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CP737 737 (OEM Greek)
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CP775 775 (OEM Baltic)
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CP850 850 (OEM Latin 1, Western European)
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CP852 852 (OEM Latin 2, Central European)
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CP855 855 (OEM Cyrillic)
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CP857 857 (OEM Turkish)
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CP858 858 (OEM Latin 1 + Euro Symbol)
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CP862 862 (OEM Hebrew)
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CP866 866 (OEM Russian)
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CP874 874 (ANSI/OEM Thai)
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CP1125 1125 (OEM Ukraine)
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CP1250 1250 (ANSI Central European)
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CP1251 1251 (ANSI Cyrillic)
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CP1252 1252 (ANSI Latin 1, Western European)
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CP1253 1253 (ANSI Greek)
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CP1254 1254 (ANSI Turkish)
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CP1255 1255 (ANSI Hebrew)
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CP1256 1256 (ANSI Arabic)
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CP1257 1257 (ANSI Baltic)
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CP1258 1258 (ANSI/OEM Vietnamese)
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ISO-8859-1 28591 (ISO-8859-1)
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ISO-8859-2 28592 (ISO-8859-2)
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ISO-8859-3 28593 (ISO-8859-3)
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ISO-8859-4 28594 (ISO-8859-4)
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ISO-8859-5 28595 (ISO-8859-5)
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ISO-8859-6 28596 (ISO-8859-6)
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ISO-8859-7 28597 (ISO-8859-7)
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ISO-8859-8 28598 (ISO-8859-8)
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ISO-8859-9 28599 (ISO-8859-9)
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ISO-8859-10 - (not available)
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ISO-8859-11 - (not available)
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ISO-8859-13 28563 (ISO-8859-13)
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ISO-8859-14 - (not available)
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ISO-8859-15 28565 (ISO-8859-15)
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ISO-8859-16 - (not available)
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SJIS 932 (ANSI/OEM Japanese)
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GBK 936 (ANSI/OEM Simplified Chinese)
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Big5 950 (ANSI/OEM Traditional Chinese)
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JIS 50220 (ISO2022 Japanese w/o halfwidth Katakana)
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eucJP 51932 (EUC Japanese)
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eucKR 51949 (EUC Korean)
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UTF-8 65001 (UTF-8)
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</screen>
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</sect2>
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</sect1>
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<sect1 id="setup-files"><title>Customizing bash</title>
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<para>
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To set up bash so that cut and paste work properly, click on the
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"Properties" button of the window, then on the "Misc" tab. Make sure
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that "QuickEdit mode" and "Insert mode" are checked. These settings
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will be remembered next time you run bash from that shortcut. Similarly
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you can set the working directory inside the "Program" tab. The entry
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"%HOME%" is valid, but requires that you set <envar>HOME</envar> in
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the Windows environment.
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</para>
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<para>
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Your home directory should contain three initialization files
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that control the behavior of bash. They are
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<filename>.profile</filename>, <filename>.bashrc</filename> and
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<filename>.inputrc</filename>. The Cygwin base installation creates
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stub files when you start bash for the first time.</para>
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<para>
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<filename>.profile</filename> (other names are also valid, see the bash man
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page) contains bash commands. It is executed when bash is started as login
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shell, e.g. from the command <command>bash --login</command>.
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This is a useful place to define and
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export environment variables and bash functions that will be used by bash
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and the programs invoked by bash. It is a good place to redefine
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<envar>PATH</envar> if needed. We recommend adding a ":." to the end of
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<envar>PATH</envar> to also search the current working directory (contrary
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to DOS, the local directory is not searched by default). Also to avoid
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delays you should either <command>unset</command> <envar>MAILCHECK</envar>
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or define <envar>MAILPATH</envar> to point to your existing mail inbox.
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</para>
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<para>
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<filename>.bashrc</filename> is similar to
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<filename>.profile</filename> but is executed each time an interactive
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bash shell is launched. It serves to define elements that are not
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inherited through the environment, such as aliases. If you do not use
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login shells, you may want to put the contents of
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<filename>.profile</filename> as discussed above in this file
|
|
instead.
|
|
</para>
|
|
|
|
<para>
|
|
<screen>
|
|
shopt -s nocaseglob
|
|
</screen>
|
|
will allow bash to glob filenames in a case-insensitive manner.
|
|
Note that <filename>.bashrc</filename> is not called automatically for login
|
|
shells. You can source it from <filename>.profile</filename>.
|
|
</para>
|
|
|
|
<para>
|
|
<filename>.inputrc</filename> controls how programs using the readline
|
|
library (including <command>bash</command>) behave. It is loaded
|
|
automatically. For full details see the <literal>Function and Variable
|
|
Index</literal> section of the GNU <systemitem>readline</systemitem> manual.
|
|
Consider the following settings:
|
|
<screen>
|
|
# Ignore case while completing
|
|
set completion-ignore-case on
|
|
# Make Bash 8bit clean
|
|
set meta-flag on
|
|
set convert-meta off
|
|
set output-meta on
|
|
</screen>
|
|
The first command makes filename completion case insensitive, which can
|
|
be convenient in a Windows environment. The next three commands allow
|
|
<command>bash</command> to display 8-bit characters, useful for
|
|
languages with accented characters. Note that tools that do not use
|
|
<systemitem>readline</systemitem> for display, such as
|
|
<command>less</command> and <command>ls</command>, require additional
|
|
settings, which could be put in your <filename>.bashrc</filename>:
|
|
<screen>
|
|
alias less='/bin/less -r'
|
|
alias ls='/bin/ls -F --color=tty --show-control-chars'
|
|
</screen>
|
|
</para>
|
|
|
|
</sect1>
|
|
|