sed删除空行、换行符的方法

# cat file.txt

1

2

  

3

   

4

          

5

                

6

# sed '/^\s*$/d' file.txt  #删除空行
1

2

3

4

5

6

查看编译安装的mysql5.5之后版本，编译时cmake 所使用的参数
# cd /usr/local/mysql5.5/docs
# vim INFO_BIN  （其中 Pointer size: 8 一行之后的内容就是所要的参数，需要注意的是，这里的参数的书写格式并不是在执行 cmake 命令时参数的标准格式 ，使用的时候要去掉 :BOOL或 PATH: 等字符）

===== Information about the build process: =====
Build was run at 2014-09-13 23:14:29 on host 'rhel5-8-1.breeze.com'

Build was done on  Linux-2.6.18-308.el5 using i686
Build was done using cmake 3.0.2

===== Compiler flags used (from the 'sql/' subdirectory): =====
# compile C with /usr/bin/cc
# compile CXX with /usr/bin/c++
C_DEFINES = -DHAVE_CONFIG_H -DHAVE_EVENT_SCHEDULER -DMYSQL_SERVER
CXX_DEFINES = -DHAVE_CONFIG_H -DHAVE_EVENT_SCHEDULER -DMYSQL_SERVER

Pointer size: 4

===== Feature flags used: =====
-- Cache values
CMAKE_BUILD_TYPE:STRING=RelWithDebInfo
CMAKE_INSTALL_PREFIX:PATH=/usr/local/mysql5.5
COMMUNITY_BUILD:BOOL=ON
ENABLED_PROFILING:BOOL=ON
ENABLE_DEBUG_SYNC:BOOL=ON
ENABLE_GCOV:BOOL=OFF
INSTALL_LAYOUT:STRING=STANDALONE
MYSQL_DATADIR:PATH=/usr/local/mysql5.5/var
MYSQL_MAINTAINER_MODE:BOOL=OFF
TMPDIR:PATH=P_tmpdir
WITH_ARCHIVE_STORAGE_ENGINE:BOOL=OFF
WITH_ASAN:BOOL=OFF
WITH_BLACKHOLE_STORAGE_ENGINE:BOOL=OFF
WITH_DEBUG:BOOL=OFF
WITH_EMBEDDED_SERVER:BOOL=OFF
WITH_EXTRA_CHARSETS:STRING=all
WITH_FEDERATED_STORAGE_ENGINE:BOOL=OFF
WITH_INNOBASE_STORAGE_ENGINE:BOOL=ON
WITH_LIBEDIT:BOOL=ON
WITH_LIBWRAP:BOOL=OFF
WITH_PARTITION_STORAGE_ENGINE:BOOL=ON
WITH_PERFSCHEMA_STORAGE_ENGINE:BOOL=ON
WITH_PIC:BOOL=OFF
WITH_READLINE:BOOL=OFF
WITH_SSL:STRING=no
WITH_UNIT_TESTS:BOOL=ON
WITH_VALGRIND:BOOL=OFF
WITH_ZLIB:STRING=system

===== EOF =====

复制编译参数到build-config文件，因为sed是按行处理文本的，每次只读入一行到内部模式空间内。

因此要删除换行符，需要用sed的N命令全部读入（append方式）所有内容后再用s命令全局替换换行符为空。

[root@localhost mysql]# sed 's/^/-D/g' build-config
-DCMAKE_INSTALL_PREFIX=/usr/local/mysql
-DCOMMUNITY_BUILD=ON
-DENABLED_PROFILING=ON
-DENABLE_DEBUG_SYNC=ON
-DENABLE_GCOV=OFF
-DEVENT_LIBRARY=EVENT_LIBRARY-NOTFOUND
-DGROFF=/usr/bin/groff
-DINSTALL_LAYOUT=STANDALONE
-DMYSQL_DATADIR=/var/lib/mysql
-DNOT_FOR_DISTRIBUTION=OFF
-DNROFF=/usr/bin/nroff
-DUSE_ARIA_FOR_TMP_TABLES=ON
-DWITH_ARCHIVE_STORAGE_ENGINE=OFF
-DWITH_ARIA_STORAGE_ENGINE=ON
-DWITH_BLACKHOLE_STORAGE_ENGINE=ON
-DWITH_EMBEDDED_SERVER=OFF
-DWITH_EXTRA_CHARSETS=all
-DWITH_FEDERATEDX_STORAGE_ENGINE=OFF
-DWITH_FEEDBACK=OFF
-DWITH_LIBWRAP=OFF
-DWITH_PARTITION_STORAGE_ENGINE=ON
-DWITH_PERFSCHEMA_STORAGE_ENGINE=ON
-DWITH_PIC=OFF
-DWITH_QUERY_CACHE_INFO=OFF
-DWITH_READLINE=1
-DWITH_SAFEMALLOC=AUTO
-DWITH_SPHINX_STORAGE_ENGINE=OFF

[root@localhost mysql]# sed -n 'N;N;N;N;s/\n/ /g;p' build-config
-DCMAKE_INSTALL_PREFIX=/usr/local/mysql -DCOMMUNITY_BUILD=ON -DENABLED_PROFILING=ON -DENABLE_DEBUG_SYNC=ON -DENABLE_GCOV=OFF
-DEVENT_LIBRARY=EVENT_LIBRARY-NOTFOUND -DGROFF=/usr/bin/groff -DINSTALL_LAYOUT=STANDALONE -DMYSQL_DATADIR=/var/lib/mysql -DNOT_FOR_DISTRIBUTION=OFF
-DNROFF=/usr/bin/nroff -DUSE_ARIA_FOR_TMP_TABLES=ON -DWITH_ARCHIVE_STORAGE_ENGINE=OFF -DWITH_ARIA_STORAGE_ENGINE=ON -DWITH_BLACKHOLE_STORAGE_ENGINE=ON
-DWITH_EMBEDDED_SERVER=OFF -DWITH_EXTRA_CHARSETS=all -DWITH_FEDERATEDX_STORAGE_ENGINE=OFF -DWITH_FEEDBACK=OFF -DWITH_LIBWRAP=OFF
-DWITH_PARTITION_STORAGE_ENGINE=ON -DWITH_PERFSCHEMA_STORAGE_ENGINE=ON -DWITH_PIC=OFF -DWITH_QUERY_CACHE_INFO=OFF -DWITH_READLINE=1

用sed做还得考虑要读入多少行的问题，所以这里其实用awk做会更简单。

就上面这个例子：

awk -v RS="" '{gsub("\n"," ");print}' build-config

设置记录分隔符（）为空，即将所有文件内容看作一条记录（默认是一行一条记录）。

用awk的内置函数gsub全局替换换行符为空格，之后print打印即可。

mysqlnd是什么
http://lylgxy0704wht.blog.163.com/blog/static/57048039201541534414179/

cmake报错，补充安装依赖包

yum install -y gcc gcc-c++
yum install -y ncurses-devel.x86_64
yum install -y cmake.x86_64
yum install -y libaio.x86_64
yum install -y bison.x86_64
yum install -y gcc-c++.x86_64