假设我有一个未安装的块设备/dev/sda
,我想用 替换 的所有MyPassWord
实例XXXXXXXXXX
。 (希望我的目标是显而易见的。)
做到这一点最简单的方法是什么?
答案1
你可以这样做:
#! /usr/bin/env python
device = '/dev/sdi'
old_pattern = "MyPassWord"
new_pattern = "XXXXXXXXXX"
assert len (old_pattern) == len(new_pattern)
BS = 1024 ** 2 # 1 Mb buffer
# read a few bytes more to account for occurences of the pattern on the edge
READSIZE = BS + len(old_pattern)
offset = 0
with open(device, 'r+b') as fp:
assert isinstance(fp, file)
while True:
try:
fp.seek(offset)
except IOError:
#print 'offset', offset
#raise
break
buf = fp.read(READSIZE)
occurences = buf.count(old_pattern)
if occurences:
print offset, occurences
fp.seek(offset)
fp.write(buf.replace(old_pattern, new_pattern))
fp.flush()
offset += BS
在顶部替换适当的设备名称。
您必须运行脚本root
并确保完成后重新挂载设备,因为文件内容的系统缓冲区不会收到更改通知。