在读取文件时忽略带有匹配单词的空行和grep行

Question

我正在尝试编写将从文件中读取的示例代码 a）忽略空行 b）仅显示以dm开头的行 但它给我错误，不知道该怎么做， 任何人都可以给我一些亮点

def _find_dm_name():
        with open (IOSTAT_OUTPUT,'r')as f:
                for line in f:
                  lines = (line.rstrip() for line in f)
                  lines = list(line for line in lines if line)
                  if re.match("(dm-)", lines):
                   content=lines
        return content
if __name__ == '__main__':
        dm_name=_find_dm_name()
        print dm_name


Traceback (most recent call last):
  File "test.py", line 47, in <module>
    dm_name=_find_dm_name()
  File "test.py", line 41, in _find_dm_name
    if re.match("(.*)", lines):
  File "/usr/lib64/python2.6/re.py", line 137, in match
    return _compile(pattern, flags).match(string)
TypeError: expected string or buffer

即使我试试这个

def _find_dm_name():

        with open (IOSTAT_OUTPUT,'r')as f:
                for line in f:
                  if re.match("(dm-*)", line):
                   content=line
        return content

它只给我最后一行

但是如何获得只匹配dm- +的所有行忽略任何空行