fuser命令--谁打开了我的文件

fuser命令学习

fuser：使用文件或者套节字来表示识别进程。我常用的他的两个功能：查看我需要的进程和我要杀死我查到的进程。

比如当你想umount光驱的时候，结果系统提示你设备正在使用或者正忙，可是你又找不到到底谁使用了他。这个时候fuser可派上用场了。

[root@lancy sbin]# eject

umount: /media/cdrom: device is busy

umount: /media/cdrom: device is busy

eject: unmount of `/media/cdrom' failed

[root@lancy sbin]# fuser /mnt/cdrom

/mnt/cdrom: 4561c 5382c

[root@lancy sbin]# ps -ef |egrep '(4561|5382)' |grep -v grep

root 4561 4227 0 20:13 pts/1 00:00:00 bash

root 5382 4561 0 21:42 pts/1 00:00:00 vim Autorun.inf

示例中，我想弹出光驱，系统告诉我设备忙着，于是采用fuser命令，参数是你文件或scoket，fuser将查出那些使用了他。

4561c,5382c表示目前用两个进程在占用着/mnt/cdrom，分别是4561,5382,进程ID后的字母表示占用资源的方式，有下面几种表示：

c 当前路径(current directory.)我的理解是表示这个资源的占用是以文件目录方式，也就是进进入了需要释放的资源的路径，这是最常用的资源占用方式。

e 正在运行可执行文件（executable being run.），比如运行了光盘上的某个程序

f 打开文件（ open file），缺省模式下f忽略。所以上面的例子中，虽然是开打了光盘上的Autorun.inf文件，但是给出的标识是c，而不是f。

r root目录（root directory）.没有明白什么意思，难道是说进入了/root这个特定目录？

m mmap文件或者共享库( mmap’ed file or shared library).这应该是说某个进程使用了你要释放的资源的某个共享文件。

在查找的同时，你还可定指定一些参数，比如

-k 杀死这些正在访问这些文件的进程。除非使用-signal修改信号，否则将发送SIGKILL信号。

-i 交互模式

-l 列出所有已知的信号名称。

-n 空间，选择不同的名字空间，可是file,udp,tcp。默认是file，也就是文件。

-signal 指定发送的信号，而不是缺省的SIGKILL

-4 仅查询IPV4套接字

-6 仅查询IPV6套接字

- 重置所有的选项，将信息设回SIGKILL

再看下面的例子

[root@lancy sbin]# fuser -l

HUP INT QUIT ILL TRAP ABRT IOT BUS FPE KILL USR1 SEGV USR2 PIPE ALRM TERM

STKFLT CHLD CONT STOP TSTP TTIN TTOU URG XCPU XFSZ VTALRM PROF WINCH IO PWR SYS

UNUSED

现在我们试试fuser -k的威力：

[root@lancy sbin]# fuser -k /mnt/cdrom

/mnt/cdrom: 4561c 5382c

kill 5382: 没有那个进程

No automatic removal. Please use umount /media/cdrom

[root@lancy sbin]# eject

套节字方式的使用：

[root@lancy sbin]# fuser -4 -n tcp 3306

here: 3306

3306/tcp: 5595

[root@lancy sbin]# ps -ef |grep 5595 |grep -v grep

mysql 5595 5563 0 22:24 pts/0 00:00:00 /usr/libexec/mysqld --defaults-file=/etc/my.cnf --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-locking --socket=/var/lib/mysql/mysql.sock

[root@lancy sbin]# fuser -4 -n tcp 80

here: 80

80/tcp: 5685 5688 5689 5690 5691 5692 5693 5694 5695

List Open Files: lsof andfuser

The function of these commands is very similar. The goal is to determine what processes have certain files open. lsof is freeware and thus freely compilable under all Unixes. It is available by default under Linux only.

The main difference between lsof and fuser is that lsof takes both files/filesystems and PIDs as arguments whereas fuser only accepts files/filesystems.

lsof:

lsof stands for list open files. It lists information about files that are currently open by processes.

In the absence of any options, lsof lists all open files belonging to all active processes

To list all open files for login name ``abe'', or user ID 1234 you would use the-u option. To list files being used by process 456, process 123, or process 789, you would use the-p flag. Putting these criteria together, we would have a command that looks like this:

lsof -p 456,123,789 -u 1234,abe

The command to list all open files on device /dev/hd4, would look like this:

lsof /dev/hd4

To find the process that has /u/abe/foo open, use:

lsof /u/abe/foo

fuser:

fuser is more widely available (under AIX, HP-UX, IRIX, Linux, Solaris, Tru64 UNIX, and others) and can only be run as root. It displays the process ID numbers of processes using the specified files or file systems. In the default display mode, each file name is followed by a letter denoting the type of access (these codes differ from vendor to vendor):

aif the process is using the file as its trace file in /proc (IRIX)cif the process is using the file as its current directoryeif the process is using the file as the executable being runfif the process is using the file as an open file (Linux)mif the process is using the file as a mmaped or shared lib (Linux)oif the process is using the file as an open file (IRIX, Solaris, Tru64 UNIX))pif the process is using the file as the parent of its current directory (Tru64 UNIX)rif the process is using the file as root directorysif the process is using the file as a shared lib (AIX)tif the process is using the file as its text file (Solaris)yif the process is using the file as its controlling terminal (IRIX)

Here is an example of fuser running under Linux:

linux# /usr/sbin/fuser /

/: 1r 1c 2r 2c 3r 3c 4r 4c

252r 252c 275r 275c 286r 286c 300r 314r 328r 328c 342r

342c 356r 356c 374r 374c 385r 385c 396r 396c 411r 411c

412r 412c 413r 413c 414r 414c 415r 415c 416r 416c 417r

417c 418r 418c 419r 419c 420r 420c 455r 470r 470c 485r

485c 500r 500c 538r 538c 539r 539c 540r 540c 541r 541c

542r 542c 543r 543c 544r 544c 546r 546c 548r 548c 551r

551c 556r 569r 591r 597r 610r 612r 614r 614c 618r 626r

628r 636r 646r 7090r 7090c 7092r 7243r 7288r 7288c 7290r 7303r