今天优化Box Anemometer慢日志导入的脚本，在调试时pt-query-digest一直卡在Reading from STDIN ...不动，而别一台机器顺利执行成功。 查看帮助
pt-query-digest --help
pt-query-digest analyzes MySQL queries from slow, general, and binary log files.
It can also analyze queries from C<SHOW PROCESSLIST> and MysqL protocol data
from tcpdump. By default, queries are grouped by fingerprint and reported in
descending order of query time (i.e. the slowest queries first). If no C<FILES>
are given, the tool reads C<STDIN>. The optional C<DSN> is used for certain
options like L<"--since"> and L<"--until">. For more details, please use the
--help option, or try 'perldoc /usr/local/percona-toolkit/bin/pt-query-digest'
for complete documentation.
意思是如果没有给定FILE则等待输入，ls命令验证是文件不存在，原因是跟另一台机器的文件名不一样，拷贝命令过来直接执行肯定不行啦，把文件名改为本机的慢日志名称即可执行完成
