grep命令-v参数过滤以井号、分号开头的注释信息行及空白行

grep命令-v参数（反向选择）分别去掉所有以#（井号）和;（分号）开头的注释信息行，对于剩余的空白行可以再用^$来表示并反选过滤

[root@rhel7 samba]# cat smb.conf | grep -v "#" | grep -v ";" | grep -v "^$"
[global]
        workgroup = MYGROUP
        server string = Samba Server Version %v
        log file = /var/log/samba/log.%m
        max log size =
        security = user
        passdb backend = tdbsam
        load printers = yes
        cups options = raw
[homes]
        comment = Home Directories
        browseable = no
        writable = yes
[printers]
        comment = All Printers
        path = /var/spool/samba
        browseable = no
        guest ok = no
        writable = no
        printable = yes