/dev/zero 与 /dev/null

/dev/zero,是一个输入设备，你可你用它来初始化文件。

/dev/zero------该设备无穷尽地提供0，可以使用任何你需要的数目——设备提供的要多的多。他可以用于向设备或文件写入字符串0。

/dev/zero 可以说就是一个无底洞，可以向里面放多少东西它都不会觉得多

oracle@localhost oracle]$if=/dev/zero of=./test.txt bs=1k count=1

oracle@localhost oracle]$ ls -l

total 4

-rw-r--r-- 1 oracle dba 1024 Jul 15 16:56 test.txt

eg,

find / -name access_log 2>/dev/null

这样，一些诸如一些错误信息就不会显示出来。

/dev/zero：

In Unix-like operating systems, /dev/zero is a special file that provides as many null characters (ASCII NULL, 0x00; not ASCII character "digit zero", "0", 0x30)
as are read from it. One of the typical uses is to provide a character stream for overwriting information. Another might be to generate a clean file of a certain size. Using mmap to map /dev/zero to RAM is the BSD way of implementing shared memory.

# Initialise partition (important note: trying out this command will eradicate

# any files that were on the partition, make sure you have a backup of any important data.)

dd if=/dev/zero of=/dev/hda7

# Create a large empty file called 'foobar'

dd if=/dev/zero of=foobar count=1000 bs=1000

Like /dev/null, /dev/zero acts as a source and sink for data. All writes to /dev/zero succeed with no other effects (the same as for /dev/null, although /dev/null
is the more commonly used data sink); all reads on /dev/zero return as many NULs as characters requested.