gnu coreutils
https://www.gnu.org/software/coreutils/manual/coreutils.html#toc_Printing-text 目录列表
https://www.gnu.org/software/coreutils/manual/coreutils.html#File-permissions
文件权限被包括在coreutils包中。
http://blog.sina.com.cn/s/blog_8a41719c0100wf98.html 这里面的翻译可以参照一下
The file mode bits have two parts: the file permission bits, which control ordinary access to the file, and special mode bits, which affect only some files.
文件模式位有两部分：文件权限位，它控制着文件的普通访问，特殊模式位，它只影响一些文件。
限制删除标志（restricted deletion flag）也称为 sticky 标志
27 File permissions 2015/5/11，此节（27节）文档已阅读完毕
27.5 Directories and the Set-User-ID and Set-Group-ID Bits
On most systems, if a directory's set-group-ID bit is set, newly created subfiles inherit the same group as the directory, and newly created subdirectories inherit the set-group-ID bit of the parent directory.
在多数系统中，如果一个目录的sgid位设置，新建子文件继承和目录相同的组，新建子目录继承父目录的sgid。
On a few systems, a directory's set-user-ID bit has a similar effect on the ownership of new subfiles and the set-user-ID bits of new subdirectories.
在少数系统中，一个目录的suid有一个相似的影响在新建子文件的属主和
These mechanisms let users share files more easily, by lessening the need to use chmod or chown to share new files.
这些机制让用户分享文件更简单，减少使用chmod或chown来分享新文件的需要。
These convenience mechanisms rely on the set-user-ID and set-group-ID bits of directories.
这些方便的机制依赖于目录的suid和sgid
If commands like chmod and mkdir routinely cleared these bits on directories, the mechanisms would be less convenient and it would be harder to share files.
如果像chmod和mkdir这类命令老一套地清除这些位，机制会不太方便并且分享文件将变得困难。
Therefore, a command like chmod does not affect the set-user-ID or set-group-ID bits of a directory unless the user specifically mentions them in a symbolic mode, or uses an operator numeric mode such as ‘=755’, or sets them in a numeric mode, or clears them in a numeric mode that has five or more octal digits.
因此，像chmod的这类命令不影响一个目录suid或sgid位，除非用户在符号模式中特别提到他们，或者使用一个数字模式的操作如‘=755’，或者在数字模式中设置他们，或者清理他们在一个数字模式有5个或更多8进制位。
For example, on systems that support set-group-ID inheritance:
例如，在支持sgid继承的系统上：
This behavior is a GNU extension. Portable scripts should not rely on requests to set or clear these bits on directories, as POSIX allows implementations to ignore these requests.
这个行为是一个GNU扩展。可移植的脚本不依赖请求设置或清除这些位关于目录，而POSIX允许实现忽略这些请求。
The GNU behavior with numeric modes of four or fewer digits is intended for scripts portable to systems that preserve these bits;
数字模式的4个或更少的位的GNU行为试图为脚本移植到保留这些位的系统;
the behavior with numeric modes of five or more digits is for scripts portable to systems that do not preserve the bits.
数字模式的5个或更多的位的行为为脚本移植到不需要保留这些位的系统中。
1 Introduction 2015/5/13，此节（1节）文档已阅读完毕
This manual is a work in progress: many sections make no attempt to explain basic concepts in a way suitable for novices.
这个手册是一个进展的工作：很多部分不试图以一种适合新手的方式去解释基本的概念。
Thus, if you are interested, please get involved in improving this manual. The entire GNU community will benefit.
如果你有兴趣，请加入我们来改进这个手册。这样整个GNU社区将受益。
The GNU utilities documented here are mostly compatible with the POSIX standard.
这里记录的GNU实用工具大多数兼容POSIX标准。
Please report bugs to bug-coreutils@gnu.org. Remember to include the version number, machine architecture, input files, and any other information needed to reproduce the bug: your input, what you expected, what you got, and why it is wrong. Diffs are welcome, but please include a description of the problem as well, since this is sometimes difficult to infer. See Bugs.
请报告bugs到bug-coreutils@gnu.org。记住包括版本号，机器架构，输入文件，和任何其它能重现bug所需要的信息：你的输入，期盼的结果，实际的结果，和为什么是错误的，diffs are welcome，但也请包括一个问题描述，因为有时难于推断。参见bugs。
This manual was originally derived from the Unix man pages in the distributions, which were written by David MacKenzie and updated by Jim Meyering.
这本手册原始的来源于发行版的 unix man 手册页，这些手册页由David MacKenzie书写并由Jim Meyering更新。
What you are reading now is the authoritative documentation for these utilities; the man pages are no longer being maintained.
你现在阅读的东西是这些工具的权限文档;man pages 不再维护。
The original fmt man page was written by Ross Paterson. Francois Pinard did the initial conversion to Texinfo format.
原始的fmt 手册页由ross paterson 编写。francois pinard 做了初始转换工作，到texinfo 格式。
Karl Berry did the indexing, some reorganization, and editing of the results. Brian Youmans of the Free Software Foundation office staff combined the manuals for textutils, fileutils, and sh-utils to produce the present omnibus manual.
karl berry 制作索引，一些重新组织，和结果的编辑。fsf办公室职员 brain youmans 组合了textutils，fileutils，和sh-utils手册，来产出目前综合性的手册。
Richard Stallman contributed his usual invaluable insights to the overall process.
richard stallman 在全过程贡献了他的宝贵的意见。
2 Common options
Certain options are available in all of these programs. Rather than writing identical descriptions for each of the programs, they are described here. (In fact, every GNU program accepts (or should accept) these options.)
某些选项所有的程序中可用。并不是为每一个程序书写完全相同的描述（事实上，每一个GNU程序都接受这些选项。）
Normally options and operands can appear in any order, and programs act as if all the options appear before any operands. For example, ‘sort -r passwd -t :’ acts like ‘sort -r -t : passwd’, since ‘:’ is an option-argument of -t. However, if the POSIXLY_CORRECT environment variable is set, options must appear before operands, unless otherwise specified for a particular command.
正常的选项和操作对象可以以任意顺序出现， 例如，
A few programs can usefully have trailing operands with leading ‘-’. With such a program, options must precede operands even if POSIXLY_CORRECT is not set, and this fact is noted in the program description. For example, the env command's options must appear before its operands, since in some cases the operands specify a command that itself contains options.
一些程序
Most programs that accept long options recognize unambiguous abbreviations of those options. For example, ‘rmdir --ignore-fail-on-non-empty’ can be invoked as ‘rmdir --ignore-fail’ or even ‘rmdir --i’. Ambiguous options, such as ‘ls --h’, are identified as such.
大多数程序接收可识别的长选项来明确这些选项的缩写。例如
Some of these programs recognize the --help and --version options only when one of them is the sole command line argument. For these programs, abbreviations of the long options are not always recognized.
仅当它们之一是唯一的命令行参数时。对这些程序来说，长选项的缩写并不总是可识别。
16 Conditions
This section describes commands that are primarily useful for their exit status, rather than their output.
这部分描述了命令的退出状态的主要用法，而不是它们的输出。
Thus, they are often used as the condition of shell if statements, or as the last command in a pipeline.
因此，它们经常被用作shell if 语句的条件，或者作为在管道线上的最后一个命令。
16.4expr: Evaluate expressions
expr求一个表达式的值并且写它的结果到标准输出上。每一个表达式token必须是一个独立的参数。
操作数要么是整型，要么是字符串。整型由一个或多个十进制数字组成，expr转换出现在操作数位置上的任意为一个整数或一个字符串，依赖于应用在它身上的操作。
字符串expr本身不引用，
However, regardless of whether it is quoted, a string operand should not be a parenthesis or any of `expr''s operators like
不过，不管是否引用，一个字符串操作数不应该是一个括号或任何的expr的操作符，
`+', so you cannot safely pass an arbitrary string `$str' to expr merely by quoting it to the shell.
像+，因此你不能安全的传递一个任意字符串 `$str`给expr仅仅引用它到shell。
One way to work around this is to use the GNU extension `+', (e.g., `+ "$str" = foo');
变通这个的一种方法是使用GNU 扩展'+', '+ "$str" = foo'
a more portable way is to use `" $str"' and to adjust the rest of the expression to take the leading space into account (e.g., `" $str" = " foo"').
更方便的方法是使用 " $str" 并且调节表达式的其余部分来使前导空格到，'" $str" = " foo"'
'+ "$str" = foo'
'" $str" = " foo"'
Options must precede operands.
选项必须在操作数之前。
`expr' supports the usual logical connectives and relations.
expr 支持平常的逻辑连接符和关系符
These are higher precedence than either the string or numeric operators (previous sections).
这些比不管是字符串还是数字操作符有更高优先级
Here is the list, lowest-precedence operator first.
这是一个列表，首先是最低优先级操作符。
15.2printf: Format and print data
The format argument is reused as necessary to convert all the given arguments. For example, the command ‘printf %s a b’ outputs ‘ab’.
格式化参数根据需要重用来转换给定的参数。例如，命令‘printf %s a b’输出'ab'。
Missing arguments are treated as null strings or as zeros, depending on whether the context expects a string or a number. For example, the command ‘printf %sx%d’ prints ‘x0’.
参数丢失被认为空串或零，依赖于环境是否希望字符串或数字。
An additional escape, ‘c’, causes printf to produce no further output. For example, the command ‘printf 'A%sCcD%sF' B E’ prints ‘ABC’.
一个额外的转义 'c',引发printf不产生更进一步的输出。例如，命令‘printf 'A%sCcD%sF' B E’打印'ABC'。
The hexadecimal escape sequence ‘xhh’ has at most two digits, as opposed to C where it can have an unlimited number of digits.
16进制转义序列‘xhh’有至多两个数字，与C截然相反，它不限制数字数量。
For example, the command ‘printf 'x07e'’ prints two bytes, whereas the C statement ‘printf ("x07e")’ prints just one.
例如，命令‘printf 'x07e'’打印两个字节，然而C语句‘printf ("x07e")’只打印一个字节。
printf has an additional directive, ‘%b’, which prints its argument string with ‘’ escapes interpreted in the same way as in the format string,
printf有一个额外的指令，‘%b’，它打印它的参数字符串
except that octal escapes are of the form ‘ ooo’ where ooo is 0 to 3 octal digits. If ‘ooo’ is nine-bit value, ignore the ninth bit. If a precision is also given, it limits the number of bytes printed from the converted string.
Numeric arguments must be single C constants, possibly with leading ‘+’ or ‘-’. For example, ‘printf %.4d -3’ outputs ‘-0003’.
数字参数必须是单个C常量，可能以+或-开头。例如
If the leading character of a numeric argument is ‘"’ or ‘'’ then its value is the numeric value of the immediately following character.
如果一个数字参数的开头字符是“或者‘，那么它的值是紧跟字符的数字值。
Any remaining characters are silently ignored if the POSIXLY_CORRECT environment variable is set; otherwise, a warning is printed.
如果POSIXLY_CORRECT环境变量设置，那么任何剩余的字符都被忽略;否则警告被打印。
For example, ‘printf "%d" "'a"’ outputs ‘97’ on hosts that use the ASCII character set, since ‘a’ has the numeric value 97 in ASCII.
例如，‘printf "%d" "'a"’在使用ascii字符集的主机上输出'97'，因为a有一个ascii的数字97值。
gnu grub
http://blog.csdn.net/wuhui_gdnt/article/category/856724 已经有人将grub手册进行翻译，这是地址
http://www.gnu.org/software/grub/manual/grub.html
12 GRUB’s user interface
GRUB has both a simple menu interface for choosing preset entries from a configuration file,
grub既有一个简单的菜单接口用来从配置文件中选择预设的项，
and a highly flexible command-line for performing any desired combination of boot commands.
也有一个高度灵活的命令行来完成任何希望的启动命令组合。
GRUB looks for its configuration file as soon as it is loaded. If one is found, then the full menu interface is activated using whatever entries were found in the file.
grub寻找配置文件尽可能快的。如果找到，那么完全菜单接口被激活使用在配置文件中找到的项。
If you choose the command-line menu option, or if the configuration file was not found, then GRUB drops to the command-line interface.
如果你选择命令行菜单项，或者配置文件没找到，那么grub进入命令行接口。
• Command-line interface: The flexible command-line interface
• Menu interface: The simple menu interface
• Menu entry editor: Editing a menu entry
http://www.gnu.org/software/grub/manual/multiboot/multiboot.html
The Multiboot Specification is an open standard describing how a boot loader can load an x86 operating system kernel. The specification allows any compliant boot loader implementation to boot any compliant operating system kernel. Thus, it allows different operating systems and boot loaders to work together and interoperate, without the need for operating system–specific boot loaders. As a result, it also allows easier coexistence of different operating systems on a single computer, which is also known as multi-booting.
The specification was originally created in 1995 and developed by the Free Software Foundation. GNU Hurd, VMware ESXi, Xen, and L4 microkernels all need to be booted using this method. GNU GRUB is the reference implementation used in the GNU operating system and other operating systems. As of January 2015, the latest version of Multiboot Specification is 0.6.96, defined in 2009.
interoperate 互操作
coexistence 共存