正则表达式之去除空行

在Linux中搭建服务的时候难免要查看配置文件，一般包含#号的行都是不会被执行的

故我们在查看配置文件的时候，特别的配置文件较长的时候，要用到正则表达式

[root@db code]# more my.cnf 
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html

[mysqld]

 Remove leading # and set to the amount of RAM for the most important data
 cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
 innodb_buffer_pool_size = 128M

 Remove leading # to turn on a very important data integrity option: logging
 changes to the binary log between backups.
 log_bin

# These are commonly set, remove the # and set as required.
# basedir = .....
# datadir = .....
 port = .....
 server_id = .....
 socket = .....

# Remove leading # to set options mainly useful for reporting servers.
 The server defaults are faster for transactions and fast SELECTs.
 Adjust sizes as needed, experiment to find the optimal values.
 join_buffer_size = 128M
 sort_buffer_size = 2M
# read_rnd_buffer_size = 2M 

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 

以此代码为例，用正则挑选出对我们有用的行，并且去除空行

[root@db code]# grep -v ^'#' my.cnf |grep -v ^$
[mysqld]
 Remove leading # and set to the amount of RAM for the most important data
 cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
 innodb_buffer_pool_size = 128M
 Remove leading # to turn on a very important data integrity option: logging
 changes to the binary log between backups.
 log_bin
 port = .....
 server_id = .....
 socket = .....
 The server defaults are faster for transactions and fast SELECTs.
 Adjust sizes as needed, experiment to find the optimal values.
 join_buffer_size = 128M
 sort_buffer_size = 2M
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES