暂时只翻译了一部分，sorry！
NAME | SYNOPSIS（概要） | DESCRIPTION | NOTES（注意） | BUGS | SEE ALSO（参见） | COLOPHON（版权页）
ENVIRON(7) Linux Programmer's Manual（Linux 程序员手册） ENVIRON(7)（环境）
NAME top
environ - user environment（用户环境）
SYNOPSIS（概要） top
extern char **environ;（外部字符环境）
DESCRIPTION（描述） top
The variable environ points to an array of pointers to strings called the "environment".
环境变量指向一个指针数组，指针数组指向被调用的字符串“环境”。
The last pointer in this array has the value NULL.
这个数组中的最后一个指针的值为NULL。
(This variable must be declared in the user program, but is declared in the header file
if the _GNU_SOURCE feature test macro is defined.)
这个变量必须在用户程序中声明，如果_GNU_SOURCE（c c++里的变量)测试宏已经定义，则这个变量应该在头文件申明。c c++ 都有头文件
This array of strings is made available to the process by the exec(3) call that started the process.
这个字符串数组由启动进程的exec(3)调用提供给进程。
When a child process is created via fork(2), it inherits a copy of its parent's environment.
当通过fork(2)创建子进程时，它继承父进程环境的副本。
By convention the strings in environ have the form "name=value".
根据约定，环境中的字符串具有“name=value”的形式。
Common examples are:（通用示例）
USER The name of the logged-in user (used by some BSD-derived
programs).
LOGNAME
The name of the logged-in user (used by some System-V derived
programs).
HOME A user's login directory, set by login(1) from the password
file passwd(5).
LANG The name of a locale to use for locale categories when not
overridden by LC_ALL or more specific environment variables（更多具体的环境变量）
such as LC_COLLATE （核对）, LC_CTYPE（函数）, LC_MESSAGES, LC_MONETARY（货币金融）,
LC_NUMERIC（数值）, and LC_TIME (see locale(7) for further details（更进一步的细节） of
the LC_* environment variables).
"PATH" The sequence of directory prefixes that sh(1) and many other
programs apply in searching for a file known by an incomplete （不完整的）
pathname. The prefixes are separated by ':'. (Similarly one
has CDPATH used by some shells（壳，cmd Shell.这是一个用 C 语言编写的程序,它是用户使用 Linux 的桥梁。Shell 既是一种命令语言,又是一种程序设计语言）
to find the target of a change directory command, MANPATH used by man(1) to find manual pages, and so on)
PWD The current working directory. Set by some shells.
SHELL The pathname of the user's login shell.
TERM The terminal type for which output is to be prepared.
PAGER The user's preferred utility to display text files.（用户显示文本文件的首选实用程序）
EDITOR/VISUAL
The user's preferred utility （adj. 优先的；首选的 ，首选的效用） to edit text files.
Names may be placed in the shell's environment by the export command
in sh(1), or by the setenv command if you use csh(1).
The initial environment of the shell is populated in various ways,
such as definitions from /etc/environment that are processed by
pam_env(8) for all users at login time (on systems that employ
pam(8)). In addition, various shell initialization scripts, such as
the system-wide /etc/profile script and per-user initializations
script may include commands that add variables to the shell's
environment; see the manual page of your preferred shell（） for details（有关详情信息）.
Bourne-style shells support the syntax
NAME=value command
to create an environment variable definition(环境变量定义) only in the scope of the
process that executes command. Multiple variable definitions,
separated by white space, may precede （优先）command.
Arguments may also be placed in the environment at the point of an
exec(3). A C program can manipulate its environment using the
functions getenv(3), putenv(3), setenv(3), and unsetenv(3).
Note that the behavior of many programs and library routines （库） is
influenced（adj. 受影响的） by the presence or value of certain （这里译为某些） environment variables.
注意，许多程序和库例程的行为是受某些环境变量的存在或值的影响。
Examples include the following:
* The variables LANG, LANGUAGE, NLSPATH, LOCPATH, LC_ALL,
LC_MESSAGES, and so on influence locale handling; see catopen(3),
gettext(3), and locale(7).
* TMPDIR influences the path prefix of names created by tempnam(3)
and other routines（例程）, and the temporary directory（临时目录） used by sort(1)
and other programs.
* LD_LIBRARY_PATH, LD_PRELOAD, and other LD_* variables influence
the behavior of the dynamic loader/linker.
* POSIXLY_CORRECT makes certain programs and library routines follow
the prescriptions of POSIX.
* The behavior of malloc(3) is influenced by MALLOC_* variables.
* The variable HOSTALIASES gives the name of a file containing
aliases to be used with gethostbyname(3).
* TZ and TZDIR give timezone information used by tzset(3) and
through that by functions like ctime(3), localtime(3), mktime(3),
strftime(3). See also tzselect(8).
* TERMCAP gives information on how to address a given terminal (or
gives the name of a file containing such information).
* COLUMNS and LINES tell applications about the window size,
possibly overriding the actual size.
* PRINTER or LPDEST may specify the desired printer to use. See
lpr(1).
NOTES top
The prctl(2) PR_SET_MM_ENV_START and PR_SET_MM_ENV_END operations can
be used to control the location of the process's environment.
BUGS top
Clearly there is a security risk here. Many a system command has
been tricked into mischief by a user who specified unusual values for
IFS or LD_LIBRARY_PATH.
There is also the risk of name space pollution. Programs like make
and autoconf allow overriding of default utility names from the
environment with similarly named variables in all caps. Thus one
uses CC to select the desired C compiler (and similarly MAKE, AR, AS,
FC, LD, LEX, RM, YACC, etc.). However, in some traditional uses such
an environment variable gives options for the program instead of a
pathname. Thus, one has MORE, LESS, and GZIP. Such usage is
considered mistaken, and to be avoided in new programs. The authors
of gzip should consider renaming their option to GZIP_OPT.
SEE ALSO top
bash(1), csh(1), env(1), login(1), printenv(1), sh(1), tcsh(1),
execve(2), clearenv(3), exec(3), getenv(3), putenv(3), setenv(3),
unsetenv(3), locale(7), ld.so(8), pam_env(8)
COLOPHON top
This page is part of release 4.16 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux
