auto/options脚本解析-part2
接上一章，此文我们来解析auto/options脚本。此脚本主要用来设定配置选项。
参看：
1) http://blog.csdn.net/poechant/article/details/7327206
2) http://man.linuxde.net/sed
1. auto/options脚本
在分析脚本之前，我们这里贴出其源代码：
# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.
help=no
NGX_PREFIX=
NGX_SBIN_PATH=
NGX_MODULES_PATH=
NGX_CONF_PREFIX=
NGX_CONF_PATH=
NGX_ERROR_LOG_PATH=
NGX_PID_PATH=
NGX_LOCK_PATH=
NGX_USER=
NGX_GROUP=
NGX_BUILD=
CC=${CC:-cc}
CPP=
NGX_OBJS=objs
NGX_DEBUG=NO
NGX_CC_OPT=
NGX_LD_OPT=
CPU=NO
NGX_RPATH=NO
NGX_TEST_BUILD_DEVPOLL=NO
NGX_TEST_BUILD_EVENTPORT=NO
NGX_TEST_BUILD_EPOLL=NO
NGX_TEST_BUILD_SOLARIS_SENDFILEV=NO
NGX_PLATFORM=
NGX_WINE=
EVENT_FOUND=NO
EVENT_SELECT=NO
EVENT_POLL=NO
USE_THREADS=NO
NGX_FILE_AIO=NO
NGX_IPV6=NO
HTTP=YES
NGX_HTTP_LOG_PATH=
NGX_HTTP_CLIENT_TEMP_PATH=
NGX_HTTP_PROXY_TEMP_PATH=
NGX_HTTP_FASTCGI_TEMP_PATH=
NGX_HTTP_UWSGI_TEMP_PATH=
NGX_HTTP_SCGI_TEMP_PATH=
HTTP_CACHE=YES
HTTP_CHARSET=YES
HTTP_GZIP=YES
HTTP_SSL=NO
HTTP_V2=NO
HTTP_SSI=YES
HTTP_POSTPONE=NO
HTTP_REALIP=NO
HTTP_XSLT=NO
HTTP_IMAGE_FILTER=NO
HTTP_SUB=NO
HTTP_ADDITION=NO
HTTP_DAV=NO
HTTP_ACCESS=YES
HTTP_AUTH_BASIC=YES
HTTP_AUTH_REQUEST=NO
HTTP_USERID=YES
HTTP_SLICE=NO
HTTP_AUTOINDEX=YES
HTTP_RANDOM_INDEX=NO
HTTP_STATUS=NO
HTTP_GEO=YES
HTTP_GEOIP=NO
HTTP_MAP=YES
HTTP_SPLIT_CLIENTS=YES
HTTP_REFERER=YES
HTTP_REWRITE=YES
HTTP_PROXY=YES
HTTP_FASTCGI=YES
HTTP_UWSGI=YES
HTTP_SCGI=YES
HTTP_PERL=NO
HTTP_MEMCACHED=YES
HTTP_LIMIT_CONN=YES
HTTP_LIMIT_REQ=YES
HTTP_EMPTY_GIF=YES
HTTP_BROWSER=YES
HTTP_SECURE_LINK=NO
HTTP_DEGRADATION=NO
HTTP_FLV=NO
HTTP_MP4=NO
HTTP_GUNZIP=NO
HTTP_GZIP_STATIC=NO
HTTP_UPSTREAM_HASH=YES
HTTP_UPSTREAM_IP_HASH=YES
HTTP_UPSTREAM_LEAST_CONN=YES
HTTP_UPSTREAM_KEEPALIVE=YES
HTTP_UPSTREAM_ZONE=YES
# STUB
HTTP_STUB_STATUS=NO
MAIL=NO
MAIL_SSL=NO
MAIL_POP3=YES
MAIL_IMAP=YES
MAIL_SMTP=YES
STREAM=NO
STREAM_SSL=NO
STREAM_LIMIT_CONN=YES
STREAM_ACCESS=YES
STREAM_UPSTREAM_HASH=YES
STREAM_UPSTREAM_LEAST_CONN=YES
STREAM_UPSTREAM_ZONE=YES
DYNAMIC_MODULES=
NGX_ADDONS=
NGX_ADDON_DEPS=
DYNAMIC_ADDONS=
USE_PCRE=NO
PCRE=NONE
PCRE_OPT=
PCRE_CONF_OPT=
PCRE_JIT=NO
USE_OPENSSL=NO
OPENSSL=NONE
USE_MD5=NO
MD5=NONE
MD5_OPT=
MD5_ASM=NO
USE_SHA1=NO
SHA1=NONE
SHA1_OPT=
SHA1_ASM=NO
USE_ZLIB=NO
ZLIB=NONE
ZLIB_OPT=
ZLIB_ASM=NO
USE_PERL=NO
NGX_PERL=perl
USE_LIBXSLT=NO
USE_LIBGD=NO
USE_GEOIP=NO
NGX_GOOGLE_PERFTOOLS=NO
NGX_CPP_TEST=NO
NGX_LIBATOMIC=NO
NGX_CPU_CACHE_LINE=
NGX_POST_CONF_MSG=
opt=
for option
do
opt="$opt `echo $option | sed -e \"s/\(--[^=]*=\)\(.* .*\)/\1'\2'/\"`"
case "$option" in
-*=*) value=`echo "$option" | sed -e 's/[-_a-zA-Z0-9]*=//'` ;;
*) value="" ;;
esac
case "$option" in
--help) help=yes ;;
--prefix=) NGX_PREFIX="!" ;;
--prefix=*) NGX_PREFIX="$value" ;;
--sbin-path=*) NGX_SBIN_PATH="$value" ;;
--modules-path=*) NGX_MODULES_PATH="$value" ;;
--conf-path=*) NGX_CONF_PATH="$value" ;;
--error-log-path=*) NGX_ERROR_LOG_PATH="$value";;
--pid-path=*) NGX_PID_PATH="$value" ;;
--lock-path=*) NGX_LOCK_PATH="$value" ;;
--user=*) NGX_USER="$value" ;;
--group=*) NGX_GROUP="$value" ;;
--crossbuild=*) NGX_PLATFORM="$value" ;;
--build=*) NGX_BUILD="$value" ;;
--builddir=*) NGX_OBJS="$value" ;;
--with-select_module) EVENT_SELECT=YES ;;
--without-select_module) EVENT_SELECT=NONE ;;
--with-poll_module) EVENT_POLL=YES ;;
--without-poll_module) EVENT_POLL=NONE ;;
--with-threads) USE_THREADS=YES ;;
--with-file-aio) NGX_FILE_AIO=YES ;;
--with-ipv6) NGX_IPV6=YES ;;
--without-http) HTTP=NO ;;
--without-http-cache) HTTP_CACHE=NO ;;
--http-log-path=*) NGX_HTTP_LOG_PATH="$value" ;;
--http-client-body-temp-path=*) NGX_HTTP_CLIENT_TEMP_PATH="$value" ;;
--http-proxy-temp-path=*) NGX_HTTP_PROXY_TEMP_PATH="$value" ;;
--http-fastcgi-temp-path=*) NGX_HTTP_FASTCGI_TEMP_PATH="$value" ;;
--http-uwsgi-temp-path=*) NGX_HTTP_UWSGI_TEMP_PATH="$value" ;;
--http-scgi-temp-path=*) NGX_HTTP_SCGI_TEMP_PATH="$value" ;;
--with-http_ssl_module) HTTP_SSL=YES ;;
--with-http_v2_module) HTTP_V2=YES ;;
--with-http_realip_module) HTTP_REALIP=YES ;;
--with-http_addition_module) HTTP_ADDITION=YES ;;
--with-http_xslt_module) HTTP_XSLT=YES ;;
--with-http_xslt_module=dynamic) HTTP_XSLT=DYNAMIC ;;
--with-http_image_filter_module) HTTP_IMAGE_FILTER=YES ;;
--with-http_image_filter_module=dynamic)
HTTP_IMAGE_FILTER=DYNAMIC ;;
--with-http_geoip_module) HTTP_GEOIP=YES ;;
--with-http_geoip_module=dynamic)
HTTP_GEOIP=DYNAMIC ;;
--with-http_sub_module) HTTP_SUB=YES ;;
--with-http_dav_module) HTTP_DAV=YES ;;
--with-http_flv_module) HTTP_FLV=YES ;;
--with-http_mp4_module) HTTP_MP4=YES ;;
--with-http_gunzip_module) HTTP_GUNZIP=YES ;;
--with-http_gzip_static_module) HTTP_GZIP_STATIC=YES ;;
--with-http_auth_request_module) HTTP_AUTH_REQUEST=YES ;;
--with-http_random_index_module) HTTP_RANDOM_INDEX=YES ;;
--with-http_secure_link_module) HTTP_SECURE_LINK=YES ;;
--with-http_degradation_module) HTTP_DEGRADATION=YES ;;
--with-http_slice_module) HTTP_SLICE=YES ;;
--without-http_charset_module) HTTP_CHARSET=NO ;;
--without-http_gzip_module) HTTP_GZIP=NO ;;
--without-http_ssi_module) HTTP_SSI=NO ;;
--without-http_userid_module) HTTP_USERID=NO ;;
--without-http_access_module) HTTP_ACCESS=NO ;;
--without-http_auth_basic_module) HTTP_AUTH_BASIC=NO ;;
--without-http_autoindex_module) HTTP_AUTOINDEX=NO ;;
--without-http_status_module) HTTP_STATUS=NO ;;
--without-http_geo_module) HTTP_GEO=NO ;;
--without-http_map_module) HTTP_MAP=NO ;;
--without-http_split_clients_module) HTTP_SPLIT_CLIENTS=NO ;;
--without-http_referer_module) HTTP_REFERER=NO ;;
--without-http_rewrite_module) HTTP_REWRITE=NO ;;
--without-http_proxy_module) HTTP_PROXY=NO ;;
--without-http_fastcgi_module) HTTP_FASTCGI=NO ;;
--without-http_uwsgi_module) HTTP_UWSGI=NO ;;
--without-http_scgi_module) HTTP_SCGI=NO ;;
--without-http_memcached_module) HTTP_MEMCACHED=NO ;;
--without-http_limit_conn_module) HTTP_LIMIT_CONN=NO ;;
--without-http_limit_req_module) HTTP_LIMIT_REQ=NO ;;
--without-http_empty_gif_module) HTTP_EMPTY_GIF=NO ;;
--without-http_browser_module) HTTP_BROWSER=NO ;;
--without-http_upstream_hash_module) HTTP_UPSTREAM_HASH=NO ;;
--without-http_upstream_ip_hash_module) HTTP_UPSTREAM_IP_HASH=NO ;;
--without-http_upstream_least_conn_module)
HTTP_UPSTREAM_LEAST_CONN=NO ;;
--without-http_upstream_keepalive_module) HTTP_UPSTREAM_KEEPALIVE=NO ;;
--without-http_upstream_zone_module) HTTP_UPSTREAM_ZONE=NO ;;
--with-http_perl_module) HTTP_PERL=YES ;;
--with-http_perl_module=dynamic) HTTP_PERL=DYNAMIC ;;
--with-perl_modules_path=*) NGX_PERL_MODULES="$value" ;;
--with-perl=*) NGX_PERL="$value" ;;
# STUB
--with-http_stub_status_module) HTTP_STUB_STATUS=YES ;;
--with-mail) MAIL=YES ;;
--with-mail=dynamic) MAIL=DYNAMIC ;;
--with-mail_ssl_module) MAIL_SSL=YES ;;
# STUB
--with-imap)
MAIL=YES
NGX_POST_CONF_MSG="$NGX_POST_CONF_MSG
$0: warning: the \"--with-imap\" option is deprecated, \
use the \"--with-mail\" option instead"
;;
--with-imap_ssl_module)
MAIL_SSL=YES
NGX_POST_CONF_MSG="$NGX_POST_CONF_MSG
$0: warning: the \"--with-imap_ssl_module\" option is deprecated, \
use the \"--with-mail_ssl_module\" option instead"
;;
--without-mail_pop3_module) MAIL_POP3=NO ;;
--without-mail_imap_module) MAIL_IMAP=NO ;;
--without-mail_smtp_module) MAIL_SMTP=NO ;;
--with-stream) STREAM=YES ;;
--with-stream=dynamic) STREAM=DYNAMIC ;;
--with-stream_ssl_module) STREAM_SSL=YES ;;
--without-stream_limit_conn_module)
STREAM_LIMIT_CONN=NO ;;
--without-stream_access_module) STREAM_ACCESS=NO ;;
--without-stream_upstream_hash_module)
STREAM_UPSTREAM_HASH=NO ;;
--without-stream_upstream_least_conn_module)
STREAM_UPSTREAM_LEAST_CONN=NO ;;
--without-stream_upstream_zone_module)
STREAM_UPSTREAM_ZONE=NO ;;
--with-google_perftools_module) NGX_GOOGLE_PERFTOOLS=YES ;;
--with-cpp_test_module) NGX_CPP_TEST=YES ;;
--add-module=*) NGX_ADDONS="$NGX_ADDONS $value" ;;
--add-dynamic-module=*) DYNAMIC_ADDONS="$DYNAMIC_ADDONS $value" ;;
--with-cc=*) CC="$value" ;;
--with-cpp=*) CPP="$value" ;;
--with-cc-opt=*) NGX_CC_OPT="$value" ;;
--with-ld-opt=*) NGX_LD_OPT="$value" ;;
--with-cpu-opt=*) CPU="$value" ;;
--with-debug) NGX_DEBUG=YES ;;
--without-pcre) USE_PCRE=DISABLED ;;
--with-pcre) USE_PCRE=YES ;;
--with-pcre=*) PCRE="$value" ;;
--with-pcre-opt=*) PCRE_OPT="$value" ;;
--with-pcre-jit) PCRE_JIT=YES ;;
--with-openssl=*) OPENSSL="$value" ;;
--with-openssl-opt=*) OPENSSL_OPT="$value" ;;
--with-md5=*) MD5="$value" ;;
--with-md5-opt=*) MD5_OPT="$value" ;;
--with-md5-asm) MD5_ASM=YES ;;
--with-sha1=*) SHA1="$value" ;;
--with-sha1-opt=*) SHA1_OPT="$value" ;;
--with-sha1-asm) SHA1_ASM=YES ;;
--with-zlib=*) ZLIB="$value" ;;
--with-zlib-opt=*) ZLIB_OPT="$value" ;;
--with-zlib-asm=*) ZLIB_ASM="$value" ;;
--with-libatomic) NGX_LIBATOMIC=YES ;;
--with-libatomic=*) NGX_LIBATOMIC="$value" ;;
--test-build-devpoll) NGX_TEST_BUILD_DEVPOLL=YES ;;
--test-build-eventport) NGX_TEST_BUILD_EVENTPORT=YES ;;
--test-build-epoll) NGX_TEST_BUILD_EPOLL=YES ;;
--test-build-solaris-sendfilev) NGX_TEST_BUILD_SOLARIS_SENDFILEV=YES ;;
*)
echo "$0: error: invalid option \"$option\""
exit 1
;;
esac
done
NGX_CONFIGURE="$opt"
if [ $help = yes ]; then
cat << END
--help print this message
--prefix=PATH set installation prefix
--sbin-path=PATH set nginx binary pathname
--modules-path=PATH set modules path
--conf-path=PATH set nginx.conf pathname
--error-log-path=PATH set error log pathname
--pid-path=PATH set nginx.pid pathname
--lock-path=PATH set nginx.lock pathname
--user=USER set non-privileged user for
worker processes
--group=GROUP set non-privileged group for
worker processes
--build=NAME set build name
--builddir=DIR set build directory
--with-select_module enable select module
--without-select_module disable select module
--with-poll_module enable poll module
--without-poll_module disable poll module
--with-threads enable thread pool support
--with-file-aio enable file AIO support
--with-ipv6 enable IPv6 support
--with-http_ssl_module enable ngx_http_ssl_module
--with-http_v2_module enable ngx_http_v2_module
--with-http_realip_module enable ngx_http_realip_module
--with-http_addition_module enable ngx_http_addition_module
--with-http_xslt_module enable ngx_http_xslt_module
--with-http_xslt_module=dynamic enable dynamic ngx_http_xslt_module
--with-http_image_filter_module enable ngx_http_image_filter_module
--with-http_image_filter_module=dynamic
enable dynamic ngx_http_image_filter_module
--with-http_geoip_module enable ngx_http_geoip_module
--with-http_geoip_module=dynamic enable dynamic ngx_http_geoip_module
--with-http_sub_module enable ngx_http_sub_module
--with-http_dav_module enable ngx_http_dav_module
--with-http_flv_module enable ngx_http_flv_module
--with-http_mp4_module enable ngx_http_mp4_module
--with-http_gunzip_module enable ngx_http_gunzip_module
--with-http_gzip_static_module enable ngx_http_gzip_static_module
--with-http_auth_request_module enable ngx_http_auth_request_module
--with-http_random_index_module enable ngx_http_random_index_module
--with-http_secure_link_module enable ngx_http_secure_link_module
--with-http_degradation_module enable ngx_http_degradation_module
--with-http_slice_module enable ngx_http_slice_module
--with-http_stub_status_module enable ngx_http_stub_status_module
--without-http_charset_module disable ngx_http_charset_module
--without-http_gzip_module disable ngx_http_gzip_module
--without-http_ssi_module disable ngx_http_ssi_module
--without-http_userid_module disable ngx_http_userid_module
--without-http_access_module disable ngx_http_access_module
--without-http_auth_basic_module disable ngx_http_auth_basic_module
--without-http_autoindex_module disable ngx_http_autoindex_module
--without-http_geo_module disable ngx_http_geo_module
--without-http_map_module disable ngx_http_map_module
--without-http_split_clients_module disable ngx_http_split_clients_module
--without-http_referer_module disable ngx_http_referer_module
--without-http_rewrite_module disable ngx_http_rewrite_module
--without-http_proxy_module disable ngx_http_proxy_module
--without-http_fastcgi_module disable ngx_http_fastcgi_module
--without-http_uwsgi_module disable ngx_http_uwsgi_module
--without-http_scgi_module disable ngx_http_scgi_module
--without-http_memcached_module disable ngx_http_memcached_module
--without-http_limit_conn_module disable ngx_http_limit_conn_module
--without-http_limit_req_module disable ngx_http_limit_req_module
--without-http_empty_gif_module disable ngx_http_empty_gif_module
--without-http_browser_module disable ngx_http_browser_module
--without-http_upstream_hash_module
disable ngx_http_upstream_hash_module
--without-http_upstream_ip_hash_module
disable ngx_http_upstream_ip_hash_module
--without-http_upstream_least_conn_module
disable ngx_http_upstream_least_conn_module
--without-http_upstream_keepalive_module
disable ngx_http_upstream_keepalive_module
--without-http_upstream_zone_module
disable ngx_http_upstream_zone_module
--with-http_perl_module enable ngx_http_perl_module
--with-http_perl_module=dynamic enable dynamic ngx_http_perl_module
--with-perl_modules_path=PATH set Perl modules path
--with-perl=PATH set perl binary pathname
--http-log-path=PATH set http access log pathname
--http-client-body-temp-path=PATH set path to store
http client request body temporary files
--http-proxy-temp-path=PATH set path to store
http proxy temporary files
--http-fastcgi-temp-path=PATH set path to store
http fastcgi temporary files
--http-uwsgi-temp-path=PATH set path to store
http uwsgi temporary files
--http-scgi-temp-path=PATH set path to store
http scgi temporary files
--without-http disable HTTP server
--without-http-cache disable HTTP cache
--with-mail enable POP3/IMAP4/SMTP proxy module
--with-mail=dynamic enable dynamic POP3/IMAP4/SMTP proxy module
--with-mail_ssl_module enable ngx_mail_ssl_module
--without-mail_pop3_module disable ngx_mail_pop3_module
--without-mail_imap_module disable ngx_mail_imap_module
--without-mail_smtp_module disable ngx_mail_smtp_module
--with-stream enable TCP/UDP proxy module
--with-stream=dynamic enable dynamic TCP/UDP proxy module
--with-stream_ssl_module enable ngx_stream_ssl_module
--without-stream_limit_conn_module disable ngx_stream_limit_conn_module
--without-stream_access_module disable ngx_stream_access_module
--without-stream_upstream_hash_module
disable ngx_stream_upstream_hash_module
--without-stream_upstream_least_conn_module
disable ngx_stream_upstream_least_conn_module
--without-stream_upstream_zone_module
disable ngx_stream_upstream_zone_module
--with-google_perftools_module enable ngx_google_perftools_module
--with-cpp_test_module enable ngx_cpp_test_module
--add-module=PATH enable external module
--add-dynamic-module=PATH enable dynamic external module
--with-cc=PATH set C compiler pathname
--with-cpp=PATH set C preprocessor pathname
--with-cc-opt=OPTIONS set additional C compiler options
--with-ld-opt=OPTIONS set additional linker options
--with-cpu-opt=CPU build for the specified CPU, valid values:
pentium, pentiumpro, pentium3, pentium4,
athlon, opteron, sparc32, sparc64, ppc64
--without-pcre disable PCRE library usage
--with-pcre force PCRE library usage
--with-pcre=DIR set path to PCRE library sources
--with-pcre-opt=OPTIONS set additional build options for PCRE
--with-pcre-jit build PCRE with JIT compilation support
--with-md5=DIR set path to md5 library sources
--with-md5-opt=OPTIONS set additional build options for md5
--with-md5-asm use md5 assembler sources
--with-sha1=DIR set path to sha1 library sources
--with-sha1-opt=OPTIONS set additional build options for sha1
--with-sha1-asm use sha1 assembler sources
--with-zlib=DIR set path to zlib library sources
--with-zlib-opt=OPTIONS set additional build options for zlib
--with-zlib-asm=CPU use zlib assembler sources optimized
for the specified CPU, valid values:
pentium, pentiumpro
--with-libatomic force libatomic_ops library usage
--with-libatomic=DIR set path to libatomic_ops library sources
--with-openssl=DIR set path to OpenSSL library sources
--with-openssl-opt=OPTIONS set additional build options for OpenSSL
--with-debug enable debug logging
END
exit 1
fi
if [ $HTTP = NO ]; then
HTTP_CHARSET=NO
HTTP_GZIP=NO
HTTP_SSI=NO
HTTP_USERID=NO
HTTP_ACCESS=NO
HTTP_STATUS=NO
HTTP_REWRITE=NO
HTTP_PROXY=NO
HTTP_FASTCGI=NO
fi
if [ ".$NGX_PLATFORM" = ".win32" ]; then
NGX_WINE=$WINE
fi
NGX_SBIN_PATH=${NGX_SBIN_PATH:-sbin/nginx}
NGX_MODULES_PATH=${NGX_MODULES_PATH:-modules}
NGX_CONF_PATH=${NGX_CONF_PATH:-conf/nginx.conf}
NGX_CONF_PREFIX=`dirname $NGX_CONF_PATH`
NGX_PID_PATH=${NGX_PID_PATH:-logs/nginx.pid}
NGX_LOCK_PATH=${NGX_LOCK_PATH:-logs/nginx.lock}
if [ ".$NGX_ERROR_LOG_PATH" = ".stderr" ]; then
NGX_ERROR_LOG_PATH=
else
NGX_ERROR_LOG_PATH=${NGX_ERROR_LOG_PATH:-logs/error.log}
fi
NGX_HTTP_LOG_PATH=${NGX_HTTP_LOG_PATH:-logs/access.log}
NGX_HTTP_CLIENT_TEMP_PATH=${NGX_HTTP_CLIENT_TEMP_PATH:-client_body_temp}
NGX_HTTP_PROXY_TEMP_PATH=${NGX_HTTP_PROXY_TEMP_PATH:-proxy_temp}
NGX_HTTP_FASTCGI_TEMP_PATH=${NGX_HTTP_FASTCGI_TEMP_PATH:-fastcgi_temp}
NGX_HTTP_UWSGI_TEMP_PATH=${NGX_HTTP_UWSGI_TEMP_PATH:-uwsgi_temp}
NGX_HTTP_SCGI_TEMP_PATH=${NGX_HTTP_SCGI_TEMP_PATH:-scgi_temp}
case ".$NGX_PERL_MODULES" in
./*)
;;
.)
;;
*)
NGX_PERL_MODULES=$NGX_PREFIX/$NGX_PERL_MODULES
;;
esac2. 读取configure配置参数
(1) 变量定义
我们注意到在auto/options脚本的最开始定义了很多变量，有些设定了初始值，有些则没有。其他变量都很稀疏平常，但是我们注意到有如下一个比较特别：
CC=${CC:-cc}则句话的含义为如果CC变量没有定义，则CC定义为cc；否则为CC定义的变量值。
(2) 解析参数选项
接着在auto/options中，有如下一段：
opt=
for option
do
opt="$opt `echo $option | sed -e \"s/\(--[^=]*=\)\(.* .*\)/\1'\2'/\"`"
case "$option" in
-*=*) value=`echo "$option" | sed -e 's/[-_a-zA-Z0-9]*=//'` ;;
*) value="" ;;
esac
done这段实际上是处理./configure携带的参数选项，for循环每次对应一个参数选项option。要注意的是for循环体上面有一个全局的opt变量。这个循环体内第一个语句是最重要的：
opt="$opt `echo $option | sed -e \"s/\(--[^=]*=\)\(.* .*\)/\1'\2'/\"`"它的实际作用是匹配configure的参数选项（把匹配到的第一部分作为参数1，匹配到的第二部分作为参数2）。因此，通过循环该语句后，最后opt的值就是一个由空格分隔的参数列表。参看：正则表达式括号、中括号、大括号的区别小结
接下来是：
case "$option" in
-*=*) value=`echo "$option" | sed -e 's/[-_a-zA-Z0-9]*=//'` ;;
*) value="" ;;
esac其含义是将value赋值为参数选项值。如果该选项不符合匹配-*=*,则将value值设置为””.
再接着是匹配各参数选项：
case "$option" in
--help) help=yes ;;
--prefix=) NGX_PREFIX="!" ;;
--prefix=*) NGX_PREFIX="$value" ;;
--sbin-path=*) NGX_SBIN_PATH="$value" ;;
--modules-path=*) NGX_MODULES_PATH="$value" ;;
--conf-path=*) NGX_CONF_PATH="$value" ;;
--error-log-path=*) NGX_ERROR_LOG_PATH="$value";;
--pid-path=*) NGX_PID_PATH="$value" ;;
--lock-path=*) NGX_LOCK_PATH="$value" ;;
--user=*) NGX_USER="$value" ;;
--group=*) NGX_GROUP="$value" ;;
// 后续省略
esac各匹配的分支语句中进行配置变量的赋值。这些变量在auto/options脚本的最开始处赋予默认值。其中那些模块配置变量被赋予YES的表示默认开启，赋予NO的表示默认关闭。但他们开启与否是由这个auto/options中的case-esac语句来决定的。
还有一些安装相关的选项变量也在这里被赋值，比如:
- prefix参数值被赋予NGX_PREFIX
- sbin-path参数值被赋予NGX_SBIN_PATH
- conf-path参数值被赋予NGX_CONF_PATH
- error-log-path参数值被赋予NGX_ERROR_LOG_PATH
- pid-path参数值被赋予NGX_PID_PATH
- lock-path参数值被赋予NGX_LOCK_PATH
如果option并不符合预设的这些匹配，也就是用户使用configure脚本的时候携带的参数错误，则auto/options会匹配该语句：
*)
echo "$0: error: invalid option \"$option\""
exit 1
;;从而提示用户参数错误，并使脚本退出运行。经过多次循环，for-do-done就结束。
3. 设定NGX_CONFIGURE变量
处理完所有option后，opt就如我们上面提到的，成为由空格分隔的配置项值，并被赋给NGX_CONFIGURE变量：
NGX_CONFIGURE="$opt"4. 是否显示configure的帮助信息
再看下面这句：
if [ $help = yes ]; then
cat << END
--help print this message
--prefix=PATH set installation prefix
--sbin-path=PATH set nginx binary pathname
--modules-path=PATH set modules path
--conf-path=PATH set nginx.conf pathname
//后续省略
END
exit
fi默认情况下，$help变量值在初始化时就为no. 如果configure选项中指定了help参数，则$help参数为yes，则会运行cat命令，显示大段的帮助信息，然后退出。
5. 是否关闭HTTP功能
默认情况下HTTP的一些基本功能是被开启的，如果用户指定了--without-http参数，则变量HTTP会被赋值为NO，则下面这段代码会被被执行：
if [ $HTTP = NO ]; then
HTTP_CHARSET=NO
HTTP_GZIP=NO
HTTP_SSI=NO
HTTP_USERID=NO
HTTP_ACCESS=NO
HTTP_STATUS=NO
HTTP_REWRITE=NO
HTTP_PROXY=NO
HTTP_FASTCGI=NO
fi6.是否指定运行于Windows平台
如果显示指定了--crossbuild参数，则变量NGX_PLATFORM会被赋予当前for-do-done循环中的$value值，也就是--crossbuild的参数值，一般考虑在Windows平台使用时才会用到，看下面的语句：
if [ ".$NGX_PLATFORM" = ".win32" ]; then
NGX_WINE=$WINE
fi如果指定了--crossbuild=win32，则NGX_WINE就会被赋值了。
7. nginx配置文件路径
在加载configure的参数时，如果没有指定--config-path参数，则$NGX_CONF_PATH变量是没有值的，下面的语句会为NGX_CONF_PATH赋予conf/nginx.conf的缺省值。不过觉得完全可以再auto/options开始处和其他参数一样先指定NGX_CONF_PATH的默认值。
NGX_SBIN_PATH=${NGX_SBIN_PATH:-sbin/nginx}
NGX_MODULES_PATH=${NGX_MODULES_PATH:-modules}
NGX_CONF_PATH=${NGX_CONF_PATH:-conf/nginx.conf}
NGX_CONF_PREFIX=`dirname $NGX_CONF_PATH`
NGX_PID_PATH=${NGX_PID_PATH:-logs/nginx.pid}
NGX_LOCK_PATH=${NGX_LOCK_PATH:-logs/nginx.lock}上面如果指定参数--conf-path=/home/michael/nginx/conf/nginx.conf，则NGX_CONF_PREFIX的值就是/home/michael/nginx/conf.
8. 错误日志文件路径
如果指定了参数--error-log-path，则NGX_ERROR_LOG_PATH变量的值会被指定。根据下面的语句，如果指定的是stderr则将NGX_ERROR_LOG_PATH修改为空，即不需要错误日志文件。如果不是标准输出，且其值为空，则设置为缺省logs/error.log。
if [ ".$NGX_ERROR_LOG_PATH" = ".stderr" ]; then
NGX_ERROR_LOG_PATH=
else
NGX_ERROR_LOG_PATH=${NGX_ERROR_LOG_PATH:-logs/error.log}
fi9. HTTP相关路径
NGX_HTTP_LOG_PATH=${NGX_HTTP_LOG_PATH:-logs/access.log}
NGX_HTTP_CLIENT_TEMP_PATH=${NGX_HTTP_CLIENT_TEMP_PATH:-client_body_temp}
NGX_HTTP_PROXY_TEMP_PATH=${NGX_HTTP_PROXY_TEMP_PATH:-proxy_temp}
NGX_HTTP_FASTCGI_TEMP_PATH=${NGX_HTTP_FASTCGI_TEMP_PATH:-fastcgi_temp}
NGX_HTTP_UWSGI_TEMP_PATH=${NGX_HTTP_UWSGI_TEMP_PATH:-uwsgi_temp}
NGX_HTTP_SCGI_TEMP_PATH=${NGX_HTTP_SCGI_TEMP_PATH:-scgi_temp}10. Perl模块
如果指定了--with-perl_modules_path参数，则NGX_PERL_MODULES变量被设定。如果NGX_PERL_MODULES变量未设定值或者值为一个绝对路径，那么不做任何处理；而如果指定的是一个相对路径，则最后设定为$NGX_PREFIX/$NGX_PERL_MODULES。
case ".$NGX_PERL_MODULES" in
./*)
;;
.)
;;
*)
NGX_PERL_MODULES=$NGX_PREFIX/$NGX_PERL_MODULES
;;
esac
