我正在使用以下命令来获取管道列表:
lsof | grep PIPE
我想知道 FD 列的值是什么意思(第五个http://i.imgur.com/KHczptf.png)。我认为r
和分别w
表示read和write,但是每个字符后面的数字是什么意思?
我知道 FD 表示文件描述符,我想弄清楚列中显示的值是什么意思,如 3r、16w、20r 等。
我正在使用以下命令来获取管道列表:
lsof | grep PIPE
我想知道 FD 列的值是什么意思(第五个http://i.imgur.com/KHczptf.png)。我认为r
和分别w
表示read和write,但是每个字符后面的数字是什么意思?
我知道 FD 表示文件描述符,我想弄清楚列中显示的值是什么意思,如 3r、16w、20r 等。
文件不仅作为流打开。其中一些列在lsof
's 手册中:
FD is the File Descriptor number of the file or:
cwd current working directory;
Lnn library references (AIX);
err FD information error (see NAME column);
jld jail directory (FreeBSD);
ltx shared library text (code and data);
Mxx hex memory-mapped type number xx.
m86 DOS Merge mapped file;
mem memory-mapped file;
mmap memory-mapped device;
pd parent directory;
rtd root directory;
tr kernel trace file (OpenBSD);
txt program text (code and data);
v86 VP/ix mapped file;
FD is followed by one of these characters, describing the
mode under which the file is open:
r for read access;
w for write access;
u for read and write access;
space if mode unknown and no lock
character follows;
'-' if mode unknown and lock
character follows.
The mode character is followed by one of these lock charac-
ters, describing the type of lock applied to the file:
N for a Solaris NFS lock of unknown type;
r for read lock on part of the file;
R for a read lock on the entire file;
w for a write lock on part of the file;
W for a write lock on the entire file;
u for a read and write lock of any length;
U for a lock of unknown type;
x for an SCO OpenServer Xenix lock on part of the
file;
X for an SCO OpenServer Xenix lock on the entire
file;
space if there is no lock.
See the LOCKS section for more information on the lock
information character.
The FD column contents constitutes a single field for pars-
ing in post-processing scripts.
That is file descriptor.
More on it:
File descriptor (FD) is an abstract indicator for accessing a file. The term is generally used in POSIX operating systems.
In POSIX, a file descriptor is an integer, specifically of the C type int. There are three standard POSIX file descriptors, corresponding to the three standard streams, which presumably every process (save perhaps a daemon) should expect to have.