SYNOPSIS
lsof [ -?abChlnNOPRstUvVX ] [ -A A ] [ -c c ] [ +c c ] [ +|-d d ] [
+|-D D ] [ +|-f [cfgGn] ] [ -F [f] ] [ -g [s] ] [ -i [i] ] [ -k k ] [
+|-L [l] ] [ +|-m m ] [ +|-M ] [ -o [o] ] [ -p s ] [ +|-r [t] ] [ -S
[t] ] [ -T [t] ] [ -u s ] [ +|-w ] [ -x [fl] ] [ -z [z] ] [ -Z [Z] ] [
-- ] [names]
DESCRIPTION
Lsof revision 4.79 lists information about files opened by processes
for the following UNIX dialects:
AIX 5.[12] and 5.3-ML1
Apple Darwin 7.x and 8.x for Power Macintosh systems
FreeBSD 4.9 for x86-based systems
FreeBSD 7.0 and 8.0 for AMD64-based systems
Linux 2.1.72 and above for x86-based systems
NetBSD 1.[456], 2.x and 3.x for Alpha, x86, and SPARC-based
systems
NEXTSTEP 3.[13] for NEXTSTEP architectures
SCO OpenServer Release 5.0.6 for x86-based systems
Solaris 9 and 10
(See the DISTRIBUTION section of this manual page for information on
how to obtain the latest lsof revision.)
An open file may be a regular file, a directory, a block special file,
a character special file, an executing text reference, a library, a
stream or a network file (Internet socket, NFS file or UNIX domain
socket.) A specific file or all the files in a file system may be
selected by path.
Instead of a formatted display, lsof will produce output that can be
parsed by other programs. See the -F, option description, and the OUT-
PUT FOR OTHER PROGRAMS section for more information.
In addition to producing a single output list, lsof will run in repeat
mode. In repeat mode it will produce output, delay, then repeat the
output operation until stopped with an interrupt or quit signal. See
the +|-r [t] option description for more information.
OPTIONS
In the absence of any options, lsof lists all open files belonging to
all active processes.
If any list request option is specified, other list requests must be
specifically requested - e.g., if -U is specified for the listing of
UNIX socket files, NFS files won't be listed unless -N is also speci-
fied; or if a user list is specified with the -u option, UNIX domain
socket files, belonging to users not in the list, won't be listed
unless the -U option is also specified.
Normally list options that are specifically stated are ORed - i.e.,
it can't be used to cause ANDing of selected pairs of selection options
by placing it between them, even though its placement there is accept-
able. Wherever -a is placed, it causes the ANDing of all selection
options.
Items of the same selection set - command names, file descriptors, net-
work addresses, process identifiers, user identifiers, zone names,
security contexts - are joined in a single ORed set and applied before
the result participates in ANDing. Thus, for example, specifying
-i@aaa.bbb, -i@ccc.ddd, -a, and -ufff,ggg will select the listing of
files that belong to either login ``fff'' OR ``ggg'' AND have network
connections to either host aaa.bbb OR ccc.ddd.
Options may be grouped together following a single prefix -- e.g., the
option set ``-a -b -C'' may be stated as -abC. However, since values
are optional following +|-f, -F, -g, -i, +|-L, -o, +|-r, -S, -T, -x and
-z. when you have no values for them be careful that the following
character isn't ambiguous. For example, -Fn might represent the -F and
-n options, or it might represent the n field identifier character fol-
lowing the -F option. When ambiguity is possible, start a new option
with a `-' character - e.g., ``-F -n''. If the next option is a file
name, follow the possibly ambiguous option with ``--'' - e.g., ``-F --
name''.
Either the `+' or the `-' prefix may be applied to a group of options.
Options that don't take on separate meanings for each prefix - e.g., -i
- may be grouped under either prefix. Thus, for example, ``+M -i'' may
be stated as ``+Mi'' and the group means the same as the separate
options. Be careful of prefix grouping when one or more options in the
group does take on separate meanings under different prefixes - e.g.,
+|-M; ``-iM'' is not the same request as ``-i +M''. When in doubt, use
separate options with appropriate prefixes.
-? -h These two equivalent options select a usage (help) output
list. Lsof displays a shortened form of this output when it
detects an error in the options supplied to it, after it has
displayed messages explaining each error. (Escape the `?'
character as your shell requires.)
-a This option causes list selection options to be ANDed, as
described above.
-A A This option is available on systems configured for AFS whose
AFS kernel code is implemented via dynamic modules. It allows
the lsof user to specify A as an alternate name list file
where the kernel addresses of the dynamic modules might be
found. See the lsof FAQ (The FAQ section gives its location.)
for more information about dynamic modules, their symbols, and
how they affect lsof.
-b This option causes lsof to avoid kernel functions that might
block - lstat(2), readlink(2), and stat(2).
slash may be followed by these modifiers:
b the regular expression is a basic one.
i ignore the case of letters.
x the regular expression is an extended one
(default).
See the lsof FAQ (The FAQ section gives its location.) for
more information on basic and extended regular expressions.
The simple command specification is tested first. If that
test fails, the command regular expression is applied. If the
simple command test succeeds, the command regular expression
test isn't made. This may result in ``no command found for
regex:'' messages when lsof's -V option is specified.
+c w This option defines the maximum number of initial characters
of the name, supplied by the UNIX dialect, of the UNIX command
associated with a process to be printed in the COMMAND column.
(The lsof default is nine.)
Note that many UNIX dialects do not supply all command name
characters to lsof in the files and structures from which lsof
obtains command name. Often dialects limit the number of
characters supplied in those sources. For example, Linux
2.4.27 and Solaris 9 both limit command name length to 16
characters.
If w is zero ('0'), all command characters supplied to lsof by
the UNIX dialect will be printed.
If w is less than the length of the column title, ``COMMAND'',
it will be raised to that length.
-C This option disables the reporting of any path name components
from the kernel's name cache. See the KERNEL NAME CACHE sec-
tion for more information.
+d s This option causes lsof to search for all open instances of
directory s and the files and directories it contains at its
top level. This option does NOT descend the directory tree,
rooted at s. The +D D option may be used to request a
full-descent directory tree search, rooted at directory D.
Processing of the +d option does not follow symbolic links
within s unless the -x or -x l option is also specified. Nor
does it search for open files on file system mount points on
subdirectories of s unless the -x or -x f option is also
specified.
Note: the authority of the user of this option limits it to
searching for files that the user has permission to examine
ending member is larger than the starting one - e.g., ``0-7''
or ``3-10''. Ranges may be specified for exclusion if they
have the '^' prefix - e.g., ``^0-7'' excludes all file
descriptors 0 through 7.
Multiple file descriptor numbers are joined in a single ORed
set before participating in AND option selection.
When there are exclusion and inclusion members in the set,
lsof reports them as errors and exits with a non-zero return
code.
See the description of File Descriptor (FD) output values in
the OUTPUT section for more information on file descriptor
names.
+D D This option causes lsof to search for all open instances of
directory D and all the files and directories it contains to
its complete depth.
Processing of the +D option does not follow symbolic links
within D unless the -x or -x l option is also specified. Nor
does it search for open files on file system mount points on
subdirectories of D unless the -x or -x f option is also
specified.
Note: the authority of the user of this option limits it to
searching for files that the user has permission to examine
with the system stat(2) function.
Further note: lsof may process this option slowly and require
a large amount of dynamic memory to do it. This is because it
must descend the entire directory tree, rooted at D, calling
stat(2) for each file and directory, building a list of all
the files it finds, and searching that list for a match with
every open file. When directory D is large, these steps can
take a long time, so use this option prudently.
-D D This option directs lsof's use of the device cache file. The
use of this option is sometimes restricted. See the DEVICE
CACHE FILE section and the sections that follow it for more
information on this option.
-D must be followed by a function letter; the function letter
may optionally be followed by a path name. Lsof recognizes
these function letters:
? - report device cache file paths
b - build the device cache file
i - ignore the device cache file
r - read the device cache file
u - read and update the device cache file
When available, the b, r, and u functions may be followed by
the device cache file's path. The standard default is
.lsof_hostname in the home directory of the real user ID that
executes lsof, but this could have been changed when lsof was
configured and compiled. (The output of the -h and -?
options show the current default prefix - e.g., ``.lsof''.)
The suffix, hostname, is the first component of the host's
name returned by gethostname(2).
When available, the b function directs lsof to build a new
device cache file at the default or specified path.
The i function directs lsof to ignore the default device cache
file and obtain its information about devices via direct calls
to the kernel.
The r function directs lsof to read the device cache at the
default or specified path, but prevents it from creating a new
device cache file when none exists or the existing one is
improperly structured. The r function, when specified without
a path name, prevents lsof from updating an incorrect or out-
dated device cache file, or creating a new one in its place.
The r function is always available when it is specified with-
out a path name argument; it may be restricted by the permis-
sions of the lsof process.
When available, the u function directs lsof to read the device
cache file at the default or specified path, if possible, and
to rebuild it, if necessary. This is the default device cache
file function when no -D option has been specified.
+|-f [cfgGn]
f by itself clarifies how path name arguments are to be inter-
preted. When followed by c, f, g, G, or n in any combination
it specifies that the listing of kernel file structure infor-
mation is to be enabled (`+') or inhibited (`-').
Normally a path name argument is taken to be a file system
name if it matches a mounted-on directory name reported by
mount(8), or if it represents a block device, named in the
mount output and associated with a mounted directory name.
When +f is specified, all path name arguments will be taken to
be file system names, and lsof will complain if any are not.
This can be useful, for example, when the file system name
(mounted-on device) isn't a block device. This happens for
some CD-ROM file systems.
When -f is specified by itself, all path name arguments will
be taken to be simple files. Thus, for example, the ``-f --
/'' arguments direct lsof to search for open files with a `/'
path name, not all open files in the `/' (root) file system.
structure information:
c file structure use count (not Linux)
f file structure address (not Linux)
g file flag abbreviations (Linux 2.6.22 and up)
G file flags in hexadecimal (Linux 2.6.22 and up)
n file structure node address (not Linux)
When the prefix is minus (`-') the same characters disable the
listing of the indicated values.
File structure addresses, use counts, flags, and node
addresses may be used to detect more readily identical files
inherited by child processes and identical files in use by
different processes. Lsof column output can be sorted by out-
put columns holding the values and listed to identify identi-
cal file use, or lsof field output can be parsed by an AWK or
Perl post-filter script, or by a C program.
-F f This option specifies a character list, f, that selects the
fields to be output for processing by another program, and the
character that terminates each output field. Each field to be
output is specified with a single character in f. The field
terminator defaults to NL, but may be changed to NUL (000).
See the OUTPUT FOR OTHER PROGRAMS section for a description of
the field identification characters and the field output
process.
When the field selection character list is empty, all standard
fields are selected (except the raw device field, security
context and zone field for compatibility reasons) and the NL
field terminator is used.
When the field selection character list contains only a zero
(`0'), all fields are selected (except the raw device field
for compatibility reasons) and the NUL terminator character is
used.
Other combinations of fields and their associated field termi-
nator character must be set with explicit entries in f, as
described in the OUTPUT FOR OTHER PROGRAMS section.
When a field selection character identifies an item lsof does
not normally list - e.g., PPID, selected with -R - specifica-
tion of the field character - e.g., ``-FR'' - also selects the
listing of the item.
When the field selection character list contains the single
character `?', lsof will display a help list of the field
identification characters. (Escape the `?' character as your
shell requires.)
When specified without a PGID set that's all it does.
-i [i] This option selects the listing of files any of whose Internet
address matches the address specified in i. If no address is
specified, this option selects the listing of all Internet and
x.25 (HP-UX) network files.
If -i4 or -i6 is specified with no following address, only
files of the indicated IP version, IPv4 or IPv6, are dis-
played. (An IPv6 specification may be used only if the
dialects supports IPv6, as indicated by ``[46]'' and
``IPv[46]'' in lsof's -h or -? output.) Sequentially speci-
fying -i4, followed by -i6 is the same as specifying -i, and
vice-versa. Specifying -i4, or -i6 after -i is the same as
specifying -i4 or -i6 by itself.
Multiple addresses (up to a limit of 100) may be specified
with multiple -i options. (A port number or service name
range is counted as one address.) They are joined in a single
ORed set before participating in AND option selection.
An Internet address is specified in the form (Items in square
brackets are optional.):
[46][protocol][@hostname|hostaddr][:service|port]
where:
46 specifies the IP version, IPv4 or IPv6
that applies to the following address.
'6' may be be specified only if the UNIX
dialect supports IPv6. If neither '4' nor
'6' is specified, the following address
applies to all IP versions.
protocol is a protocol name - TCP or UDP.
hostname is an Internet host name. Unless a
specific IP version is specified, open
network files associated with host names
of all versions will be selected.
hostaddr is a numeric Internet IPv4 address in
dot form; or an IPv6 numeric address in
colon form, enclosed in brackets, if the
UNIX dialect supports IPv6. When an IP
version is selected, only its numeric
addresses may be specified.
service is an /etc/services name - e.g., smtp -
or a list of them.
port is a port number, or a list of them.
IPv6 options may be used only if the UNIX dialect supports
IPv6. To see if the dialect supports IPv6, run lsof and spec-
ify the -h or -? (help) option. If the displayed description
of the -i option contains ``[46]'' and ``IPv[46]'', IPv6 is
or hostaddr. Specify either service name list or port number
list. If a service name list is specified, the protocol may
also need to be specified if the TCP and UDP port numbers for
the service name are different. Use any case - lower or upper
- for protocol.
Service names and port numbers may be combined in a list whose
entries are separated by commas and whose numeric range
entries are separated by minus signs. There may be no embed-
ded spaces, and all service names must belong to the specified
protocol. Since service names may contain embedded minus
signs, the starting entry of a range can't be a service name;
it can be a port number, however.
Here are some sample addresses:
-i6 - IPv6 only
TCP:25 - TCP and port 25
@1.2.3.4 - Internet IPv4 host address 1.2.3.4
@[3ffe:1ebc::1]:1234 - Internet IPv6 host address
3ffe:1ebc::1, port 1234
UDP:who - UDP who service port
TCP@lsof.itap:513 - TCP, port 513 and host name lsof.itap
tcp@foo:1-10,smtp,99 - TCP, ports 1 through 10,
service name smtp, port 99, host name foo
tcp@bar:1-smtp - TCP, ports 1 through smtp, host bar
:time - either TCP or UDP time service port
-k k This option specifies a kernel name list file, k, in place of
/vmunix, /mach, etc. This option is not available under AIX
on the IBM RISC/System 6000.
-l This option inhibits the conversion of user ID numbers to
login names. It is also useful when login name lookup is
working improperly or slowly.
+|-L [l] This option enables (`+') or disables (`-') the listing of
file link counts, where they are available - e.g., they aren't
available for sockets, or most FIFOs and pipes.
When +L is specified without a following number, all link
counts will be listed. When -L is specified (the default), no
link counts will be listed.
When +L is followed by a number, only files having a link
count less than that number will be listed. (No number may
follow -L.) A specification of the form ``+L1'' will select
open files that have been unlinked. A specification of the
form ``+aL1 <file_system>'' will select unlinked open files on
the specified file system.
For other link count comparisons, use field output (-F) and a
tory, followed by a single space, followed by the device num-
ber in hexadecimal "0x" format - e.g.,
/ 0x801
Lsof can use the mount supplement file to get device numbers
for file systems when it can't get them via stat(2) or
lstat(2).
The option form +m m identifies m as a mount supplement file.
Note: the +m and +m m options are not available for all sup-
ported dialects. Check the output of lsof's -h or -? options
to see if the +m and +m m options are available.
+|-M Enables (+) or disables (-) the reporting of portmapper regis-
trations for local TCP and UDP ports. The default reporting
mode is set by the lsof builder with the HASPMAPENABLED
#define in the dialect's machine.h header file; lsof is dis-
tributed with the HASPMAPENABLED #define deactivated, so
portmapper reporting is disabled by default and must be
requested with +M. Specifying lsof's -h or -? option will
report the default mode. Disabling portmapper registration
when it is already disabled or enabling it when already
enabled is acceptable.
When portmapper registration reporting is enabled, lsof dis-
plays the portmapper registration (if any) for local TCP or
UDP ports in square brackets immediately following the port
numbers or service names - e.g., ``:1234[name]'' or
``:name[100083]''. The registration information may be a name
or number, depending on what the registering program supplied
to the portmapper when it registered the port.
When portmapper registration reporting is enabled, lsof may
run a little more slowly or even become blocked when access to
the portmapper becomes congested or stopped. Reverse the
reporting mode to determine if portmapper registration report-
ing is slowing or blocking lsof.
For purposes of portmapper registration reporting lsof consid-
ers a TCP or UDP port local if: it is found in the local part
of its containing kernel structure; or if it is located in the
foreign part of its containing kernel structure and the local
and foreign Internet addresses are the same; or if it is
located in the foreign part of its containing kernel structure
and the foreign Internet address is INADDR_LOOPBACK
(127.0.0.1). This rule may make lsof ignore some foreign
ports on machines with multiple interfaces when the foreign
Internet address is on a different interface from the local
one.
rate or consistent file offset information from its kernel
data sources, sometimes just for particular kinds of files
(e.g., socket files.) Consult the lsof FAQ (The FAQ section
gives its location.) for more information.
The -o and -s options are mutually exclusive; they can't both
be specified. When neither is specified, lsof displays what-
ever value - size or offset - is appropriate and available for
the type of the file.
-o o This option defines the number of decimal digits (o) to be
printed after the ``0t'' for a file offset before the form is
switched to ``0x...''. An o value of zero (unlimited) directs
lsof to use the ``0t'' form for all offset output.
This option does NOT direct lsof to display offset at all
times; specify -o (without a trailing number) to do that.
This option only specifies the number of digits after ``0t''
in either mixed size and offset or offset-only output. Thus,
for example, to direct lsof to display offset at all times
with a decimal digit count of 10, use:
-o -o 10
or
-oo10
The default number of digits allowed after ``0t'' is normally
8, but may have been changed by the lsof builder. Consult the
description of the -o o option in the output of the -h or -?
option to determine the default that is in effect.
-O This option directs lsof to bypass the strategy it uses to
avoid being blocked by some kernel operations - i.e., doing
them in forked child processes. See the BLOCKS AND TIMEOUTS
and AVOIDING KERNEL BLOCKS sections for more information on
kernel operations that may block lsof.
While use of this option will reduce lsof startup overhead, it
may also cause lsof to hang when the kernel doesn't respond to
a function. Use this option cautiously.
-p s This option excludes or selects the listing of files for the
processes whose optional process IDentification (PID) numbers
are in the comma-separated set s - e.g., ``123'' or
``123,^456''. (There should be no spaces in the set.)
PID numbers that begin with `^' (negation) represent exclu-
sions.
Multiple process ID numbers are joined in a single ORed set
before participating in AND option selection. However, PID
exclusions are applied without ORing or ANDing and take effect
terminated with an interrupt or quit signal.
If the prefix is `+', repeat mode will end the first cycle no
open files are listed - and of course when lsof is stopped
with an interrupt or quit signal. When repeat mode ends
because no files are listed, the process exit code will be
zero if any open files were ever listed; one, if none were
ever listed.
Lsof marks the end of each listing: if field output is in
progress (the -F, option has been specified), the marker is
`m'; otherwise the marker is ``========''. The marker is fol-
lowed by a NL character.
Repeat mode reduces lsof startup overhead, so it is more effi-
cient to use this mode than to call lsof repetitively from a
shell script, for example.
To use repeat mode most efficiently, accompany +|-r with spec-
ification of other lsof selection options, so the amount of
kernel memory access lsof does will be kept to a minimum.
Options that filter at the process level - e.g., -c, -g, -p,
-u - are the most efficient selectors.
Repeat mode is useful when coupled with field output (see the
-F, option description) and a supervising awk or Perl script,
or a C program.
-R This option directs lsof to list the Parent Process IDentifi-
cation number in the PPID column.
-s This option directs lsof to display file size at all times.
It causes the SIZE/OFF output column title to be changed to
SIZE. If the file does not have a size, nothing is displayed.
The -o (without a following decimal digit count) and -s
options are mutually exclusive; they can't both be specified.
When neither is specified, lsof displays whatever value - size
or offset - is appropriate and available for the type of file.
Since some types of files don't have true sizes - sockets,
FIFOs, pipes, etc. - lsof displays for their sizes the content
amounts in their associated kernel buffers, if possible.
-S [t] This option specifies an optional time-out seconds value for
kernel functions - lstat(2), readlink(2), and stat(2) - that
might otherwise deadlock. The minimum for t is two; the
default, fifteen; when no value is specified, the default is
used.
See the BLOCKS AND TIMEOUTS section for more information.
Not all values are reported for all UNIX dialects. Items val-
ues (when available) are reported after the item name and '='.
When the field output mode is in effect (See OUTPUT FOR OTHER
PROGRAMS.) each item appears as a field with a `T' leading
character.
-T with no following key characters disables TCP/TPI informa-
tion reporting.
-T with following characters selects the reporting of specific
TCP/TPI information:
f selects reporting of socket options,
states and values, and TCP flags and
values.
q selects queue length reporting.
s selects connection state reporting.
w selects window size reporting.
Not all selections are enabled for some UNIX dialects. State
may be selected for all dialects and is reported by default.
The -h or -? help output for the -T option will show what
selections may be used with the UNIX dialect.
When -T is used to select information - i.e., it is followed
by one or more selection characters - the displaying of state
is disabled by default, and it must be explicitly selected
again in the characters following -T. (In effect, then, the
default is equivalent to -Ts.) For example, if queue lengths
and state are desired, use -Tqs.
Socket options, socket states, some socket values, TCP flags
and one TCP value may be reported (when available in the UNIX
dialect) in the form of the names that commonly appear after
SO_, so_, SS_, TCP_ and TF_ in the dialect's header files -
most often <sys/socket.h>, <sys/socketvar.h> and
<netinet/tcp_var.h>. Consult those header files for the mean-
ing of the flags, options, states and values.
``SO='' precedes socket options and values; ``SS='', socket
states; and ``TF='', TCP flags and values.
If a flag or option has a value, the value will follow an '='
and the name -- e.g., ``SO=LINGER=5'', ``SO=QLIM=5'',
``TF=MSS=512''. The following seven values may be reported:
Name
Reported Description (Common Symbol)
KEEPALIVE keep alive time (SO_KEEPALIVE)
the lsof FAQ (The FAQ section gives its location.)
-t This option specifies that lsof should produce terse output
with process identifiers only and no header - e.g., so that
the output may be piped to kill(1). This option selects the
-w option.
-u s This option selects the listing of files for the user whose
login names or user ID numbers are in the comma-separated set
s - e.g., ``abe'', or ``548,root''. (There should be no spa-
ces in the set.)
Multiple login names or user ID numbers are joined in a single
ORed set before participating in AND option selection.
If a login name or user ID is preceded by a `^', it becomes a
negation - i.e., files of processes owned by the login name or
user ID will never be listed. A negated login name or user ID
selection is neither ANDed nor ORed with other selections; it
is applied before all other selections and absolutely excludes
the listing of the files of the process. For example, to
direct lsof to exclude the listing of files belonging to root
processes, specify ``-u^root'' or ``-u^0''.
-U This option selects the listing of UNIX domain socket files.
-v This option selects the listing of lsof version information,
including: revision number; when the lsof binary was con-
structed; who constructed the binary and where; the name of
the compiler used to construct the lsof binary; the version
number of the compiler when readily available; the compiler
and loader flags used to construct the lsof binary; and system
information, typically the output of uname's -a option.
-V This option directs lsof to indicate the items it was asked to
list and failed to find - command names, file names, Internet
addresses or files, login names, NFS files, PIDs, PGIDs, and
UIDs.
When other options are ANDed to search options, or com-
pile-time options restrict the listing of some files, lsof may
not report that it failed to find a search item when an ANDed
option or compile-time option prevents the listing of the open
file containing the located search item.
For example, ``lsof -V -iTCP@foobar -a -d 999'' may not report
a failure to locate open files at ``TCP@foobar'' and may not
list any, if none have a file descriptor number of 999. A
similar situation arises when HASSECURITY and HASNOSOCKSECU-
RITY are defined at compile time and they prevent the listing
of open files.
or directory tree (+D).
If -x is specified by itself without a following parameter,
cross-over processing of both symbolic links and file system
mount points is enabled. Note that when -x is specified with-
out a parameter, the next argument must begin with '-' or '+'.
The optional 'f' parameter enables file system mount point
cross-over processing; 'l', symbolic link cross-over process-
ing.
The -x option may not be supplied without also supplying a +d
or +D option.
-X This is a dialect-specific option.
AIX:
This IBM AIX RISC/System 6000 option requests the reporting of
executed text file and shared library references.
WARNING: because this option uses the kernel readx() function,
its use on a busy AIX system might cause an application
process to hang so completely that it can neither be killed
nor stopped. I have never seen this happen or had a report of
its happening, but I think there is a remote possibility it
could happen.
By default use of readx() is disabled. On AIX 5L and above
lsof may need setuid-root permission to perform the actions
this option requests.
The lsof builder may specify that the -X option be restricted
to processes whose real UID is root. If that has been done,
the -X option will not appear in the -h or -? help output
unless the real UID of the lsof process is root. The default
lsof distribution allows any UID to specify -X, so by default
it will appear in the help output.
When AIX readx() use is disabled, lsof may not be able to
report information for all text and loader file references,
but it may also avoid exacerbating an AIX kernel directory
search kernel error, known as the Stale Segment ID bug.
The readx() function, used by lsof or any other program to
access some sections of kernel virtual memory, can trigger the
Stale Segment ID bug. It can cause the kernel's dir_search()
function to believe erroneously that part of an in-memory copy
of a file system directory has been zeroed. Another applica-
tion process, distinct from lsof, asking the kernel to search
the directory - e.g., by using open(2) - can cause
dir_search() to loop forever, thus hanging the application
process.
reporting is not of interest.
Use this option with care and only when you are sure that the
information you want lsof to display isn't associated with
open TCP or UDP socket files.
Solaris 10 and above:
This Solaris 10 and above option requests the reporting of
cached paths for files that have been deleted - i.e., removed
with rm(1) or unlink(2).
The cached path is followed by the string `` (deleted)'' to
indicate that the path by which the file was opened has been
deleted.
Because intervening changes made to the path - i.e., renames
with mv(1) or rename(2) - are not recorded in the cached path,
what lsof reports is only the path by which the file was
opened, not its possibly different final path.
-z [z] specifies how Solaris 10 and higher zone information is to be
handled.
Without a following argument - e.g., NO z - the option speci-
fies that zone names are to be listed in the ZONE output col-
umn.
The -z option may be followed by a zone name, z. That causes
lsof to list only open files for processes in that zone. Mul-
tiple -z z option and argument pairs may be specified to form
a list of named zones. Any open file of any process in any of
the zones will be listed, subject to other conditions speci-
fied by other options and arguments.
-Z [Z] specifies how SELinux security contexts are to be handled.
This option and 'Z' field output character support are inhib-
ited when SELinux is disabled in the running Linux kernel.
See OUTPUT FOR OTHER PROGRAMS for more information on the 'Z'
field output character.
Without a following argument - e.g., NO Z - the option speci-
fies that security contexts are to be listed in the SECU-
RITY-CONTEXT output column.
The -Z option may be followed by a wildcard security context
name, Z. That causes lsof to list only open files for pro-
cesses in that security context. Multiple -Z Z option and
argument pairs may be specified to form a list of security
contexts. Any open file of any process in any of the security
contexts will be listed, subject to other conditions specified
by other options and arguments. Note that Z can be A:B:C or
*:B:C or A:B:* or *:*:C to match against the A:B:C context.
on the file system. To be considered a file system, the name
must match a mounted-on directory name in mount(8) output, or
match the name of a block device associated with a mounted-on
directory name. The +|-f option may be used to force lsof to
consider a name a file system identifier (+f) or a simple file
(-f).
If name is a path to a directory that is not the mounted-on
directory name of a file system, it is treated just as a regu-
lar file is treated - i.e., its listing is restricted to pro-
cesses that have it open as a file or as a process-specific
directory, such as the root or current working directory. To
request that lsof look for open files inside a directory name,
use the +d s and +D D options.
If a name is the base name of a family of multiplexed files -
e. g, AIX's /dev/pt[cs] - lsof will list all the associated
multiplexed files on the device that are open - e.g.,
/dev/pt[cs]/1, /dev/pt[cs]/2, etc.
If a name is a UNIX domain socket name, lsof will usually
search for it by the characters of the name alone - exactly as
it is specified and is recorded in the kernel socket struc-
ture. (See the next paragraph for an exception to that rule
for Linux.) Specifying a relative path - e.g., ./file - in
place of the file's absolute path - e.g., /tmp/file - won't
work because lsof must match the characters you specify with
what it finds in the kernel UNIX domain socket structures.
If a name is a Linux UNIX domain socket name, in one case lsof
is able to search for it by its device and inode number,
allowing name to be a relative path. The case requires that
the absolute path -- i.e., one beginning with a slash ('/') be
used by the process that created the socket, and hence be
stored in the /proc/net/unix file; and it requires that lsof
be able to obtain the device and node numbers of both the
absolute path in /proc/net/unix and name via successful
stat(2) system calls. When those conditions are met, lsof
will be able to search for the UNIX domain socket when some
path to it is is specified in name. Thus, for example, if the
path is /dev/log, and an lsof search is initiated when the
working directory is /dev, then name could be ./log.
If a name is none of the above, lsof will list any open files
whose device and inode match that of the specified path name.
If you have also specified the -b option, the only names you
may safely specify are file systems for which your mount table
supplies alternate device numbers. See the AVOIDING KERNEL
BLOCKS and ALTERNATE DEVICE NUMBERS sections for more informa-
tion.
recognize AFS files in other dialects, or may have difficulties recog-
nizing AFS files in the supported dialects.
Lsof may have trouble identifying all aspects of AFS files in supported
dialects when AFS kernel support is implemented via dynamic modules
whose addresses do not appear in the kernel's variable name list. In
that case, lsof may have to guess at the identity of AFS files, and
might not be able to obtain volume information from the kernel that is
needed for calculating AFS volume node numbers. When lsof can't com-
pute volume node numbers, it reports blank in the NODE column.
The -A A option is available in some dialect implementations of lsof
for specifying the name list file where dynamic module kernel addresses
may be found. When this option is available, it will be listed in the
lsof help output, presented in response to the -h or -?
See the lsof FAQ (The FAQ section gives its location.) for more infor-
mation about dynamic modules, their symbols, and how they affect lsof
options.
Because AFS path lookups don't seem to participate in the kernel's name
cache operations, lsof can't identify path name components for AFS
files.
SECURITY
Lsof has three features that may cause security concerns. First, its
default compilation mode allows anyone to list all open files with it.
Second, by default it creates a user-readable and user-writable device
cache file in the home directory of the real user ID that executes
lsof. (The list-all-open-files and device cache features may be dis-
abled when lsof is compiled.) Third, its -k and -m options name alter-
nate kernel name list or memory files.
Restricting the listing of all open files is controlled by the com-
pile-time HASSECURITY and HASNOSOCKSECURITY options. When HASSECURITY
is defined, lsof will allow only the root user to list all open files.
The non-root user may list only open files of processes with the same
user IDentification number as the real user ID number of the lsof
process (the one that its user logged on with).
However, if HASSECURITY and HASNOSOCKSECURITY are both defined, anyone
may list open socket files, provided they are selected with the -i
option.
When HASSECURITY is not defined, anyone may list all open files.
Help output, presented in response to the -h or -? option, gives the
status of the HASSECURITY and HASNOSOCKSECURITY definitions.
See the Security section of the 00README file of the lsof distribution
for information on building lsof with the HASSECURITY and HASNOSOCKSE-
CURITY options enabled.
Before you decide to disable the device cache file feature - enabling
it improves the performance of lsof by reducing the startup overhead of
examining all the nodes in /dev (or /devices) - read the discussion of
it in the 00DCACHE file of the lsof distribution and the lsof FAQ (The
FAQ section gives its location.)
WHEN IN DOUBT, YOU CAN TEMPORARILY DISABLE THE USE OF THE DEVICE CACHE
FILE WITH THE -Di OPTION.
When lsof user declares alternate kernel name list or memory files with
the -k and -m options, lsof checks the user's authority to read them
with access(2). This is intended to prevent whatever special power
lsof's modes might confer on it from letting it read files not normally
accessible via the authority of the real user ID.
OUTPUT
This section describes the information lsof lists for each open file.
See the OUTPUT FOR OTHER PROGRAMS section for additional information on
output that can be processed by another program.
Lsof only outputs printable (declared so by isprint(3)) 8 bit charac-
ters. Non-printable characters are printed in one of three forms: the
C ``\[bfrnt]'' form; the control character `^' form (e.g., ``^@''); or
hexadecimal leading ``\x'' form (e.g., ``\xab''). Space is non-print-
able in the COMMAND column (``\x20'') and printable elsewhere.
For some dialects - if HASSETLOCALE is defined in the dialect's
machine.h header file - lsof will print the extended 8 bit characters
of a language locale. The lsof process must be supplied a language
locale environment variable (e.g., LANG) whose value represents a known
language locale in which the extended characters are considered print-
able by isprint(3). Otherwise lsof considers the extended characters
non-printable and prints them according to its rules for non-printable
characters, stated above. Consult your dialect's setlocale(3) man page
for the names of other environment variables that may be used in place
of LANG - e.g., LC_ALL, LC_CTYPE, etc.
Lsof's language locale support for a dialect also covers wide charac-
ters - e.g., UTF-8 - when HASSETLOCALE and HASWIDECHAR are defined in
the dialect's machine.h header file, and when a suitable language
locale has been defined in the appropriate environment variable for the
lsof process. Wide characters are printable under those conditions if
iswprint(3) reports them to be. If HASSETLOCALE, HASWIDECHAR and a
suitable language locale aren't defined, or if iswprint(3) reports wide
characters that aren't printable, lsof considers the wide characters
non-printable and prints each of their 8 bits according to its rules
for non-printable characters, stated above.
Consult the answers to the "Language locale support" questions in the
lsof FAQ (The FAQ section gives its location.) for more information.
MAND'', it will be raised to that length.
If a zero w value is specified to the +c w option, the col-
umn contains all the characters of the name of the UNIX com-
mand associated with the process.
All command name characters maintained by the kernel in its
structures are displayed in field output when the command
name descriptor (`c') is specified. See the OUTPUT FOR
OTHER COMMANDS section for information on selecting field
output and the associated command name descriptor.
PID is the Process IDentification number of the process.
ZONE is the Solaris 10 and higher zone name. This column must be
selected with the -z option.
SECURITY-CONTEXT
is the SELinux security context. This column must be
selected with the -Z option. Note that the -Z option is
inhibited when SELinux is disabled in the running Linux ker-
nel.
PPID is the Parent Process IDentification number of the process.
It is only displayed when the -R option has been specified.
PGID is the process group IDentification number associated with
the process. It is only displayed when the -g option has
been specified.
USER is the user ID number or login name of the user to whom the
process belongs, usually the same as reported by ps(1).
However, on Linux USER is the user ID number or login that
owns the directory in /proc where lsof finds information
about the process. Usually that is the same value reported
by ps(1), but may differ when the process has changed its
effective user ID. (See the -l option description for
information on when a user ID number or login name is dis-
played.)
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;
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.
TYPE is the type of the node associated with the file - e.g.,
GDIR, GREG, VDIR, VREG, etc.
or ``IPv4'' for an IPv4 socket;
or ``IPv6'' for an open IPv6 network file - even if its
address is IPv4, mapped in an IPv6 address;
or ``ax25'' for a Linux AX.25 socket;
or ``inet'' for an Internet domain socket;
or ``lla'' for a HP-UX link level access file;
or ``rte'' for an AF_ROUTE socket;
or ``sock'' for a socket of unknown domain;
or ``unix'' for a UNIX domain socket;
or ``x.25'' for an HP-UX x.25 socket;
or ``BLK'' for a block special file;
or ``CHR'' for a character special file;
or ``DEL'' for a Linux map file that has been deleted;
or ``NOFD'' for a Linux /proc/<PID>/fd directory that can't
be opened -- the directory path appears in the NAME column,
followed by an error message;
or ``PAS'' for a /proc/as file;
or ``PAXV'' for a /proc/auxv file;
or ``PCRE'' for a /proc/cred file;
or ``PCTL'' for a /proc control file;
or ``PCUR'' for the current /proc process;
or ``PCWD'' for a /proc current working directory;
or ``PDIR'' for a /proc directory;
or ``PETY'' for a /proc executable type (etype);
or ``PFD'' for a /proc file descriptor;
or ``PFDR'' for a /proc file descriptor directory;
or ``PFIL'' for an executable /proc file;
or ``PFPR'' for a /proc FP register set;
or ``PGD'' for a /proc/pagedata file;
or ``PGID'' for a /proc group notifier file;
or ``PIPE'' for pipes;
or ``PLC'' for a /proc/lwpctl file;
or ``PLDR'' for a /proc/lpw directory;
or ``PLDT'' for a /proc/ldt file;
or ``PLPI'' for a /proc/lpsinfo file;
or ``PLST'' for a /proc/lstatus file;
or ``PLU'' for a /proc/lusage file;
or ``PLWG'' for a /proc/gwindows file;
or ``PLWI'' for a /proc/lwpsinfo file;
or ``PLWS'' for a /proc/lwpstatus file;
or ``POLP'' for an old format /proc light weight process
file;
or ``POPF'' for an old format /proc PID file;
or ``POPG'' for an old format /proc page data file;
or ``PORT'' for a SYSV named pipe;
or ``PREG'' for a /proc register file;
or ``PRMP'' for a /proc/rmap file;
or ``PRTD'' for a /proc root directory;
or ``PSGA'' for a /proc/sigact file;
or ``PSIN'' for a /proc/psinfo file;
or ``PSTA'' for a /proc status file;
or ``PSXSEM'' for a POSIX semaphore file;
or ``PSXSHM'' for a POSIX shared memory file;
or ``PUSG'' for a /proc/usage file;
or ``PW'' for a /proc/watch file;
or ``PXMP'' for a /proc/xmap file;
or ``REG'' for a regular file;
or ``SMT'' for a shared memory transport file;
or ``STSO'' for a stream socket;
or ``UNNM'' for an unnamed type file;
or ``XNAM'' for an OpenServer Xenix special file of unknown
type;
or ``XSEM'' for an OpenServer Xenix semaphore file;
or ``XSD'' for an OpenServer Xenix shared data file;
or the four type number octets if the corresponding name
isn't known.
FILE-ADDR contains the kernel file structure address when f has been
specified to +f;
ASYN asynchronous I/O (e.g., FASYNC)
BAS block, test, and set in use
BKIU block if in use
BL use block offsets
BSK block seek
CA copy avoid
CIO concurrent I/O
CLON clone
CLRD CL read
CR create
DF defer
DFI defer IND
DFLU data flush
DIR direct
DLY delay
DOCL do clone
DSYN data-only integrity
DTY must be a directory
EVO event only
EX open for exec
EXCL exclusive open
FSYN synchronous writes
GCDF defer during unp_gc() (AIX)
GCMK mark during unp_gc() (AIX)
GTTY accessed via /dev/tty
HUP HUP in progress
KERN kernel
KIOC kernel-issued ioctl
LCK has lock
LG large file
MBLK stream message block
MK mark
MNT mount
MSYN multiplex synchronization
NATM don't update atime
NB non-blocking I/O
NBDR no BDRM check
NBIO SYSV non-blocking I/O
NBF n-buffering in effect
NC no cache
ND no delay
NDSY no data synchronization
NET network
NFLK don't follow links
NMFS NM file system
NOTO disable background stop
NSH no share
NTTY no controlling TTY
OLRM OLR mirror
PAIO POSIX asynchronous I/O
PP POSIX pipe
R read
SWR synchronous read
SYN file integrity while writing
TCPM avoid TCP collision
TR truncate
W write
WKUP parallel I/O synchronization
WTG parallel I/O synchronization
VH vhangup pending
VTXT virtual text
XL exclusive lock
this list of names was derived from F* #define's in dialect
header files <fcntl.h>, <linux</fs.h>, <sys/fcntl.c>,
<sys/fcntlcom.h>, and <sys/file.h>; see the lsof.h header
file for a list showing the correspondence between the above
short-hand names and the header file definitions;
the second list (after the semicolon) may contain short-hand
names for kernel per-process open file flags from this ta-
ble:
ALLC allocated
BR the file has been read
BHUP activity stopped by SIGHUP
BW the file has been written
CLSG closing
CX close-on-exec (see fcntl(F_SETFD))
LCK lock was applied
MP memory-mapped
OPIP open pending - in progress
RSVW reserved wait
SHMT UF_FSHMAT set (AIX)
USE in use (multi-threaded)
NODE-ID (or INODE-ADDR for some dialects) contains a unique identi-
fier for the file node (usually the kernel vnode or inode
address, but also occasionally a concatenation of device and
node number) when n has been specified to +f;
DEVICE contains the device numbers, separated by commas, for a
character special, block special, regular, directory or NFS
file;
or ``memory'' for a memory file system node under Tru64
UNIX;
or the address of the private data area of a Solaris socket
stream;
or a kernel reference address that identifies the file (The
kernel reference address may be used for FIFO's, for exam-
ple.);
tent file offset information from its kernel data sources,
sometimes just for particular kinds of files (e.g., socket
files.) In other cases, files don't have true sizes - e.g.,
sockets, FIFOs, pipes - so lsof displays for their sizes the
content amounts it finds in their kernel buffer descriptors
(e.g., socket buffer size counts or TCP/IP window sizes.)
Consult the lsof FAQ (The FAQ section gives its location.)
for more information.
The file size is displayed in decimal; the offset is nor-
mally displayed in decimal with a leading ``0t'' if it con-
tains 8 digits or less; in hexadecimal with a leading ``0x''
if it is longer than 8 digits. (Consult the -o o option
description for information on when 8 might default to some
other value.)
Thus the leading ``0t'' and ``0x'' identify an offset when
the column may contain both a size and an offset (i.e., its
title is SIZE/OFF).
If the -o option is specified, lsof always displays the file
offset (or nothing if no offset is available) and labels the
column OFFSET. The offset always begins with ``0t'' or
``0x'' as described above.
The lsof user can control the switch from ``0t'' to ``0x''
with the -o o option. Consult its description for more
information.
If the -s option is specified, lsof always displays the file
size (or nothing if no size is available) and labels the
column SIZE. The -o and -s options are mutually exclusive;
they can't both be specified.
For files that don't have a fixed size - e.g., don't reside
on a disk device - lsof will display appropriate information
about the current size or position of the file if it is
available in the kernel structures that define the file.
NLINK contains the file link count when +L has been specified;
NODE is the node number of a local file;
or the inode number of an NFS file in the server host;
or the Internet protocol type - e. g, ``TCP'';
or ``STR'' for a stream;
or ``CCITT'' for an HP-UX x.25 socket;
or the IRQ or inode number of a Linux AX.25 socket device.
IPv6 numbers are enclosed in square brackets; IPv4
INADDR_ANY and IPv6 IN6_IS_ADDR_UNSPECIFIED addresses, and
zero port numbers are represented by an asterisk ('*'); a
UDP destination address may be followed by the amount of
time elapsed since the last packet was sent to the destina-
tion; TCP and UDP remote addresses may be followed by
TCP/TPI information in parentheses - state (e.g., ``(ESTAB-
LISHED)'', ``(Unbound)''), queue sizes, and window sizes
(not all dialects) - in a fashion similar to what netstat(1)
reports; see the -T option description or the description of
the TCP/TPI field in OUTPUT FOR OTHER PROGRAMS for more
information on state, queue size, and window size;
or the address or name of a UNIX domain socket, possibly
including a stream clone device name, a file system object's
path name, local and foreign kernel addresses, socket pair
information, and a bound vnode address;
or the local and remote mount point names of an NFS file;
or ``STR'', followed by the stream name;
or a stream character device name, followed by ``->'' and
the stream name or a list of stream module names, separated
by ``->'';
or ``STR:'' followed by the SCO OpenServer stream device and
module names, separated by ``->'';
or system directory name, `` -- '', and as many components
of the path name as lsof can find in the kernel's name cache
for selected dialects (See the KERNEL NAME CACHE section for
more information.);
or ``PIPE->'', followed by a Solaris kernel pipe destination
address;
or ``COMMON:'', followed by the vnode device information
structure's device name, for a Solaris common vnode;
or the address family, followed by a slash (`/'), followed
by fourteen comma-separated bytes of a non-Internet raw
socket address;
or the HP-UX x.25 local address, followed by the virtual
connection number (if any), followed by the remote address
(if any);
or ``(dead)'' for disassociated Tru64 UNIX files - typically
terminal files that have been flagged with the TIOCNOTTY
ioctl and closed by daemons;
or ``, CANTRCVMORE'' if receiving on the socket has been
disabled (e.g., by the shutdown(2) function);
or the local and remote addresses of a Linux IPX socket file
in the form <net>:[<node>:]<port>, followed in parentheses
by the transmit and receive queue sizes, and the connection
state;
or ``dgram'' or ``stream'' for the type UnixWare 7.1.1 and
above in-kernel UNIX domain sockets, followed by a colon
(':') and the local path name when available, followed by
``->'' and the remote path name or kernel socket address in
hexadecimal when available.
For dialects that support a ``namefs'' file system, allowing one file
to be attached to another with fattach(3C), lsof will add
``(FA:<address1><direction><address2>)'' to the NAME column.
<address1> and <address2> are hexadecimal vnode addresses. <direction>
will be ``<-'' if <address2> has been fattach'ed to this vnode whose
address is <address1>; and ``->'' if <address1>, the vnode address of
this vnode, has been fattach'ed to <address2>. <address1> may be omit-
ted if it already appears in the DEVICE column.
Lsof may add two parenthetical notes to the NAME column for open
Solaris 10 files: ``(?)'' if lsof considers the path name of question-
able accuracy; and ``(deleted)'' if the -X option has been specified
and lsof detects the open file's path name has been deleted. Consult
the lsof FAQ (The FAQ section gives its location.) for more informa-
tion on these NAME column additions.
LOCKS
Lsof can't adequately report the wide variety of UNIX dialect file
locks in a single character. What it reports in a single character is
a compromise between the information it finds in the kernel and the
limitations of the reporting format.
Moreover, when a process holds several byte level locks on a file, lsof
only reports the status of the first lock it encounters. If it is a
byte level lock, then the lock character will be reported in lower case
- i.e., `r', `w', or `x' - rather than the upper case equivalent
reported for a full file lock.
Generally lsof can only report on locks held by local processes on
local files. When a local process sets a lock on a remotely mounted
(e.g., NFS) file, the remote server host usually records the lock
state. One exception is Solaris - at some patch levels of 2.3, and in
all versions above 2.4, the Solaris kernel records information on
remote locks in local structures.
Lsof has trouble reporting locks for some UNIX dialects. Consult the
BUGS section of this manual page or the lsof FAQ (The FAQ section gives
its location.) for more information.
IDentifier (PID)). It extends to the beginning of the next PID field
or the beginning of the first file set of the process, whichever comes
first. Included in the process set are fields that identify the com-
mand, the process group IDentification (PGID) number, and the user ID
(UID) number or login name.
A file set begins with a field whose identifier is `f' (for file
descriptor). It is followed by lines that describe the file's access
mode, lock state, type, device, size, offset, inode, protocol, name and
stream module names. It extends to the beginning of the next file or
process set, whichever comes first.
When the NUL (000) field terminator has been selected with the 0 (zero)
field identifier character, lsof ends each process and file set with a
NL (012) character.
Lsof always produces one field, the PID (`p') field. All other fields
may be declared optionally in the field identifier character list that
follows the -F option. When a field selection character identifies an
item lsof does not normally list - e.g., PPID, selected with -R - spec-
ification of the field character - e.g., ``-FR'' - also selects the
listing of the item.
It is entirely possible to select a set of fields that cannot easily be
parsed - e.g., if the field descriptor field is not selected, it may be
difficult to identify file sets. To help you avoid this difficulty,
lsof supports the -F option; it selects the output of all fields with
NL terminators (the -F0 option pair selects the output of all fields
with NUL terminators). For compatibility reasons neither -F nor -F0
select the raw device field.
These are the fields that lsof will produce. The single character
listed first is the field identifier.
a file access mode
c process command name (all characters from proc or
user structure)
C file structure share count
d file's device character code
D file's major/minor device number (0x<hexadecimal>)
f file descriptor
F file structure address (0x<hexadecimal>)
G file flaGs (0x<hexadecimal>; names if +fg follows)
i file's inode number
k link count
l file's lock status
L process login name
m marker between repeated output
n file name, comment, Internet address
N node identifier (ox<hexadecimal>
o file's offset (decimal)
p process ID (always selected)
TF=<TCP flags and values> (not all dialects)
WR=<window read size> (not all dialects)
WW=<window write size> (not all dialects)
(TCP/TPI information isn't reported for all supported
UNIX dialects. The -h or -? help output for the
-T option will show what TCP/TPI reporting can be
requested.)
u process user ID
z Solaris 10 and higher zone name
Z SELinux security context (inhibited when SELinux is disabled)
0 use NUL field terminator character in place of NL
1-9 dialect-specific field identifiers (The output
of -F? identifies the information to be found
in dialect-specific fields.)
You can get on-line help information on these characters and their
descriptions by specifying the -F? option pair. (Escape the `?' char-
acter as your shell requires.) Additional information on field content
can be found in the OUTPUT section.
As an example, ``-F pcfn'' will select the process ID (`p'), command
name (`c'), file descriptor (`f') and file name (`n') fields with an NL
field terminator character; ``-F pcfn0'' selects the same output with a
NUL (000) field terminator character.
Lsof doesn't produce all fields for every process or file set, only
those that are available. Some fields are mutually exclusive: file
device characters and file major/minor device numbers; file inode num-
ber and protocol name; file name and stream identification; file size
and offset. One or the other member of these mutually exclusive sets
will appear in field output, but not both.
Normally lsof ends each field with a NL (012) character. The 0 (zero)
field identifier character may be specified to change the field termi-
nator character to a NUL (000). A NUL terminator may be easier to
process with xargs (1), for example, or with programs whose quoting
mechanisms may not easily cope with the range of characters in the
field output. When the NUL field terminator is in use, lsof ends each
process and file set with a NL (012).
Three aids to producing programs that can process lsof field output are
included in the lsof distribution. The first is a C header file,
lsof_fields.h, that contains symbols for the field identification char-
acters, indexes for storing them in a table, and explanation strings
that may be compiled into programs. Lsof uses this header file.
The second aid is a set of sample scripts that process field output,
written in awk, Perl 4, and Perl 5. They're located in the scripts
subdirectory of the lsof distribution.
The third aid is the C library used for the lsof test suite. The test
suite is written in C and uses field output to validate the correct
The default timeout value may be displayed with the -h or -? option,
and it may be changed with the -S [t] option. The minimum for t is two
seconds, but you should avoid small values, since slow system respon-
siveness can cause short timeouts to expire unexpectedly and perhaps
stop lsof before it can produce any output.
When lsof has to break a block during its access of mounted file system
information, it normally continues, although with less information
available to display about open files.
Lsof can also be directed to avoid the protection of timers and child
processes when using the kernel functions that might block by specify-
ing the -O option. While this will allow lsof to start up with less
overhead, it exposes lsof completely to the kernel situations that
might block it. Use this option cautiously.
AVOIDING KERNEL BLOCKS
You can use the -b option to tell lsof to avoid using kernel functions
that would block. Some cautions apply.
First, using this option usually requires that your system supply
alternate device numbers in place of the device numbers that lsof would
normally obtain with the lstat(2) and stat(2) kernel functions. See
the ALTERNATE DEVICE NUMBERS section for more information on alternate
device numbers.
Second, you can't specify names for lsof to locate unless they're file
system names. This is because lsof needs to know the device and inode
numbers of files listed with names in the lsof options, and the -b
option prevents lsof from obtaining them. Moreover, since lsof only
has device numbers for the file systems that have alternates, its abil-
ity to locate files on file systems depends completely on the avail-
ability and accuracy of the alternates. If no alternates are avail-
able, or if they're incorrect, lsof won't be able to locate files on
the named file systems.
Third, if the names of your file system directories that lsof obtains
from your system's mount table are symbolic links, lsof won't be able
to resolve the links. This is because the -b option causes lsof to
avoid the kernel readlink(2) function it uses to resolve symbolic
links.
Finally, using the -b option causes lsof to issue warning messages when
it needs to use the kernel functions that the -b option directs it to
avoid. You can suppress these messages by specifying the -w option,
but if you do, you won't see the alternate device numbers reported in
the warning messages.
ALTERNATE DEVICE NUMBERS
On some dialects, when lsof has to break a block because it can't get
information about a mounted file system via the lstat(2) and stat(2)
options, provided they are supported by your dialect. Check the output
of lsof's -h or -? options to see if the +m and +m m options are
available.
The ``xxxx'' portion of the field is the hexadecimal value of the file
system's device number. (Consult the st_dev field of the output of the
lstat(2) and stat(2) functions for the appropriate values for your file
systems.) Here's an example from a Sun Solaris 2.6 /etc/mnttab for a
file system remotely mounted via NFS:
nfs ignore,noquota,dev=2a40001
There's an advantage to having ``dev=xxxx'' entries in your mount table
file, especially for file systems that are mounted from remote NFS
servers. When a remote server crashes and you want to identify its
users by running lsof on one of its clients, lsof probably won't be
able to get output from the lstat(2) and stat(2) functions for the file
system. If it can obtain the file system's device number from the
mount table, it will be able to display the files open on the crashed
NFS server.
Some dialects that do not use an ASCII /etc/mtab or /etc/mnttab file
for the mount table may still provide an alternative device number in
their internal mount tables. This includes AIX, Apple Darwin, FreeBSD,
NetBSD, OpenBSD, and Tru64 UNIX. Lsof knows how to obtain the alterna-
tive device number for these dialects and uses it when its attempt to
lstat(2) or stat(2) the file system is blocked.
If you're not sure your dialect supplies alternate device numbers for
file systems from its mount table, use this lsof incantation to see if
it reports any alternate device numbers:
lsof -b
Look for standard error file warning messages that begin ``assuming
"dev=xxxx" from ...''.
KERNEL NAME CACHE
Lsof is able to examine the kernel's name cache or use other kernel
facilities (e.g., the ADVFS 4.x tag_to_path() function under Tru64
UNIX) on some dialects for most file system types, excluding AFS, and
extract recently used path name components from it. (AFS file system
path lookups don't use the kernel's name cache; some Solaris VxFS file
system operations apparently don't use it, either.)
Lsof reports the complete paths it finds in the NAME column. If lsof
can't report all components in a path, it reports in the NAME column
the file system name, followed by a space, two `-' characters, another
space, and the name components it has located, separated by the `/'
character.
Lsof can report path name components for these dialects:
FreeBSD
HP-UX
Linux
NetBSD
NEXTSTEP
OpenBSD
OPENSTEP
SCO OpenServer
SCO|Caldera UnixWare
Solaris
Tru64 UNIX
Lsof can't report path name components for these dialects:
AIX
If you want to know why lsof can't report path name components for some
dialects, see the lsof FAQ (The FAQ section gives its location.)
DEVICE CACHE FILE
Examining all members of the /dev (or /devices) node tree with stat(2)
functions can be time consuming. What's more, the information that
lsof needs - device number, inode number, and path - rarely changes.
Consequently, lsof normally maintains an ASCII text file of cached /dev
(or /devices) information (exception: the /proc-based Linux lsof where
it's not needed.) The local system administrator who builds lsof can
control the way the device cache file path is formed, selecting from
these options:
Path from the -D option;
Path from an environment variable;
System-wide path;
Personal path (the default);
Personal path, modified by an environment variable.
Consult the output of the -h, -D? , or -? help options for the current
state of device cache support. The help output lists the default
read-mode device cache file path that is in effect for the current
invocation of lsof. The -D? option output lists the read-only and
write device cache file paths, the names of any applicable environment
variables, and the personal device cache path format.
Lsof can detect that the current device cache file has been acciden-
tally or maliciously modified by integrity checks, including the compu-
tation and verification of a sixteen bit Cyclic Redundancy Check (CRC)
sum on the file's contents. When lsof senses something wrong with the
file, it issues a warning and attempts to remove the current cache file
and create a new copy, but only to a path that the process can legiti-
cache file with the mtime and ctime of the /dev (or /devices) direc-
tory, it usually detects that a new device has been added; in that case
lsof issues a warning message and attempts to rebuild the device cache
file.
Whenever lsof writes a device cache file, it sets its ownership to the
real UID of the executing process, and its permission modes to 0600,
this restricting its reading and writing to the file's owner.
LSOF PERMISSIONS THAT AFFECT DEVICE CACHE FILE ACCESS
Two permissions of the lsof executable affect its ability to access
device cache files. The permissions are set by the local system admin-
istrator when lsof is installed.
The first and rarer permission is setuid-root. It comes into effect
when lsof is executed; its effective UID is then root, while its real
(i.e., that of the logged-on user) UID is not. The lsof distribution
recommends that versions for these dialects run setuid-root.
HP-UX 11.11 and 11.23
Linux
The second and more common permission is setgid. It comes into effect
when the effective group IDentification number (GID) of the lsof
process is set to one that can access kernel memory devices - e.g.,
``kmem'', ``sys'', or ``system''.
An lsof process that has setgid permission usually surrenders the per-
mission after it has accessed the kernel memory devices. When it does
that, lsof can allow more liberal device cache path formations. The
lsof distribution recommends that versions for these dialects run set-
gid and be allowed to surrender setgid permission.
AIX 5.[12] and 5.3-ML1
Apple Darwin 7.x Power Macintosh systems
FreeBSD 4.x, 4.1x, 5.x and [67].x for x86-based systems
FreeBSD 5.x and [67].x for Alpha, AMD64 and Sparc64-based
systems
HP-UX 11.00
NetBSD 1.[456], 2.x and 3.x for Alpha, x86, and SPARC-based
systems
NEXTSTEP 3.[13] for NEXTSTEP architectures
OpenBSD 2.[89] and 3.[0-9] for x86-based systems
OPENSTEP 4.x
SCO OpenServer Release 5.0.6 for x86-based systems
SCO|Caldera UnixWare 7.1.4 for x86-based systems
Solaris 2.6, 8, 9 and 10
Tru64 UNIX 5.1
(Note: lsof for AIX 5L and above needs setuid-root permission if its -X
option is used.)
restricted when the lsof process is setuid-root. The path specified
with the r function is always read-only, even when it is available.
The b, r, and u functions are also restricted when the lsof process
runs setgid and lsof doesn't surrender the setgid permission. (See the
LSOF PERMISSIONS THAT AFFECT DEVICE CACHE FILE ACCESS section for a
list of implementations that normally don't surrender their setgid per-
mission.)
A further -D function, i (for ignore), is always available.
When available, the b function tells lsof to read device information
from the kernel with the stat(2) function and build a device cache file
at the indicated path.
When available, the r function tells lsof to read the device cache
file, but not update it. When a path argument accompanies -Dr, it
names the device cache file path. The r function is always available
when it is specified without a path name argument. If lsof is not run-
ning setuid-root and surrenders its setgid permission, a path name
argument may accompany the r function.
When available, the u function tells lsof to attempt to read and use
the device cache file. If it can't read the file, or if it finds the
contents of the file incorrect or outdated, it will read information
from the kernel, and attempt to write an updated version of the device
cache file, but only to a path it considers legitimate for the lsof
process effective and real UIDs.
DEVICE CACHE PATH FROM AN ENVIRONMENT VARIABLE
Lsof's second choice for the device cache file is the contents of the
LSOFDEVCACHE environment variable. It avoids this choice if the lsof
process is setuid-root, or the real UID of the process is root.
A further restriction applies to a device cache file path taken from
the LSOFDEVCACHE environment variable: lsof will not write a device
cache file to the path if the lsof process doesn't surrender its setgid
permission. (See the LSOF PERMISSIONS THAT AFFECT DEVICE CACHE FILE
ACCESS section for information on implementations that don't surrender
their setgid permission.)
The local system administrator can disable the use of the LSOFDEVCACHE
environment variable or change its name when building lsof. Consult
the output of -D? for the environment variable's name.
SYSTEM-WIDE DEVICE CACHE PATH
The local system administrator may choose to have a system-wide device
cache file when building lsof. That file will generally be constructed
by a special system administration procedure when the system is booted
or when the contents of /dev or /devices) changes. If defined, it is
lsof's third device cache file path choice.
.lsof_hostname.
This is lsof's fourth device cache file path choice, and is usually the
default. If a system-wide device cache file path was defined when lsof
was built, this fourth choice will be applied when lsof can't find the
system-wide device cache file. This is the only time lsof uses two
paths when reading the device cache file.
The hostname part of the second component is the base name of the exe-
cuting host, as returned by gethostname(2). The base name is defined
to be the characters preceding the first `.' in the gethostname(2)
output, or all the gethostname(2) output if it contains no `.'.
The device cache file belongs to the user ID and is readable and
writable by the user ID alone - i.e., its modes are 0600. Each dis-
tinct real user ID on a given host that executes lsof has a distinct
device cache file. The hostname part of the path distinguishes device
cache files in an NFS-mounted home directory into which device cache
files are written from several different hosts.
The personal device cache file path formed by this method represents a
device cache file that lsof will attempt to read, and will attempt to
write should it not exist or should its contents be incorrect or out-
dated.
The -Dr option without a path name argument will inhibit the writing of
a new device cache file.
The -D? option will list the format specification for constructing the
personal device cache file. The conversions used in the format speci-
fication are described in the 00DCACHE file of the lsof distribution.
MODIFIED PERSONAL DEVICE CACHE PATH
If this option is defined by the local system administrator when lsof
is built, the LSOFPERSDCPATH environment variable contents may be used
to add a component of the personal device cache file path.
The LSOFPERSDCPATH variable contents are inserted in the path at the
place marked by the local system administrator with the ``%p'' conver-
sion in the HASPERSDC format specification of the dialect's machine.h
header file. (It's placed right after the home directory in the
default lsof distribution.)
Thus, for example, if LSOFPERSDCPATH contains ``LSOF'', the home direc-
tory is ``/Homes/abe'', the host name is ``lsof.itap.purdue.edu'', and
the HASPERSDC format is the default (``%h/%p.lsof_%L''), the modified
personal device cache file path is:
/Homes/abe/LSOF/.lsof_vic
The LSOFPERSDCPATH environment variable is ignored when the lsof
process is setuid-root or when the real UID of the process is root.
to something else; change the HASPERSDC format to include the personal
path component in another place; or exclude the personal path component
entirely. Consult the output of the -D? option for the environment
variable's name and the HASPERSDC format specification.
DIAGNOSTICS
Errors are identified with messages on the standard error file.
Lsof returns a one (1) if any error was detected, including the failure
to locate command names, file names, Internet addresses or files, login
names, NFS files, PIDs, PGIDs, or UIDs it was asked to list. If the -V
option is specified, lsof will indicate the search items it failed to
list.
It returns a zero (0) if no errors were detected and if it was able to
list some information about all the specified search arguments.
When lsof cannot open access to /dev (or /devices) or one of its subdi-
rectories, or get information on a file in them with stat(2), it issues
a warning message and continues. That lsof will issue warning messages
about inaccessible files in /dev (or /devices) is indicated in its help
output - requested with the -h or >B -? options - with the message:
Inaccessible /dev warnings are enabled.
The warning message may be suppressed with the -w option. It may also
have been suppressed by the system administrator when lsof was compiled
by the setting of the WARNDEVACCESS definition. In this case, the out-
put from the help options will include the message:
Inaccessible /dev warnings are disabled.
Inaccessible device warning messages usually disappear after lsof has
created a working device cache file.
EXAMPLES
For a more extensive set of examples, documented more fully, see the
00QUICKSTART file of the lsof distribution.
To list all open files, use:
lsof
To list all open Internet, x.25 (HP-UX), and UNIX domain files, use:
lsof -i -U
To list all open IPv4 network files in use by the process whose PID is
1234, use:
lsof -i 4 -a -p 1234
lsof -i @mace
To list all open files for login name ``abe'', or user ID 1234, or
process 456, or process 123, or process 789, use:
lsof -p 456,123,789 -u 1234,abe
To list all open files on device /dev/hd4, use:
lsof /dev/hd4
To find the process that has /u/abe/foo open, use:
lsof /u/abe/foo
To send a SIGHUP to the processes that have /u/abe/bar open, use:
kill -HUP `lsof -t /u/abe/bar`
To find any open file, including an open UNIX domain socket file, with
the name /dev/log, use:
lsof /dev/log
To find processes with open files on the NFS file system named
/nfs/mount/point whose server is inaccessible, and presuming your mount
table supplies the device number for /nfs/mount/point, use:
lsof -b /nfs/mount/point
To do the preceding search with warning messages suppressed, use:
lsof -bw /nfs/mount/point
To ignore the device cache file, use:
lsof -Di
To obtain PID and command name field output for each process, file
descriptor, file device number, and file inode number for each file of
each process, use:
lsof -FpcfDi
To list the files at descriptors 1 and 3 of every process running the
lsof command for login ID ``abe'' every 10 seconds, use:
lsof -c lsof -a -d 1 -d 3 -u abe -r10
To list the current working directory of processes running a command
that is exactly four characters long and has an 'o' or 'O' in character
three, use this regular expression form of the -c c option:
IPv6) by an associated numeric colon-form address that has a run of
zeroes in it - e.g., the loop-back address - use:
lsof -i@[::1]
BUGS
Since lsof reads kernel memory in its search for open files, rapid
changes in kernel memory may produce unpredictable results.
When a file has multiple record locks, the lock status character (fol-
lowing the file descriptor) is derived from a test of the first lock
structure, not from any combination of the individual record locks that
might be described by multiple lock structures.
Lsof can't search for files with restrictive access permissions by name
unless it is installed with root set-UID permission. Otherwise it is
limited to searching for files to which its user or its set-GID group
(if any) has access permission.
The display of the destination address of a raw socket (e.g., for ping)
depends on the UNIX operating system. Some dialects store the destina-
tion address in the raw socket's protocol control block, some do not.
Lsof can't always represent Solaris device numbers in the same way that
ls(1) does. For example, the major and minor device numbers that the
lstat(2) and stat(2) functions report for the directory on which CD-ROM
files are mounted (typically /cdrom) are not the same as the ones that
it reports for the device on which CD-ROM files are mounted (typically
/dev/sr0). (Lsof reports the directory numbers.)
The support for /proc file systems is available only for BSD and Tru64
UNIX dialects, Linux, and dialects derived from SYSV R4 - e.g.,
FreeBSD, NetBSD, OpenBSD, Solaris, UnixWare.
Some /proc file items - device number, inode number, and file size -
are unavailable in some dialects. Searching for files in a /proc file
system may require that the full path name be specified.
No text (txt) file descriptors are displayed for Linux processes. All
entries for files other than the current working directory, the root
directory, and numerical file descriptors are labeled mem descriptors.
Lsof can't search for Tru64 UNIX named pipes by name, because their
kernel implementation of lstat(2) returns an improper device number for
a named pipe.
Lsof can't report fully or correctly on HP-UX 9.01, 10.20, and 11.00
locks because of insufficient access to kernel data or errors in the
kernel data. See the lsof FAQ (The FAQ section gives its location.)
for details.
The AIX SMT file type is a fabrication. It's made up for file struc-
LSOFDEVCACHE defines the path to a device cache file. See the
DEVICE CACHE PATH FROM AN ENVIRONMENT VARIABLE sec-
tion for more information.
LSOFPERSDCPATH defines the middle component of a modified personal
device cache file path. See the MODIFIED PERSONAL
DEVICE CACHE PATH section for more information.
FAQ
Frequently-asked questions and their answers (an FAQ) are available in
the 00FAQ file of the lsof distribution.
That file is also available via anonymous ftp from lsof.itap.purdue.edu
at pub/tools/unix/lsofFAQ. The URL is:
ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof/FAQ
FILES
/dev/kmem kernel virtual memory device
/dev/mem physical memory device
/dev/swap system paging device
.lsof_hostname lsof's device cache file (The suffix, hostname, is
the first component of the host's name returned by
gethostname(2).)
AUTHORS
Lsof was written by Victor A. Abell <abe@purdue.edu> of Purdue Univer-
sity. Many others have contributed to lsof. They're listed in the
00CREDITS file of the lsof distribution.
DISTRIBUTION
The latest distribution of lsof is available via anonymous ftp from the
host lsof.itap.purdue.edu. You'll find the lsof distribution in the
pub/tools/unix/lsof directory.
You can also use this URL:
ftp://lsof.itap.purdue.edu/pub/tools/unix/lsof
Lsof is also mirrored elsewhere. When you access lsof.itap.purdue.edu
and change to its pub/tools/unix/lsof directory, you'll be given a list
of some mirror sites. The pub/tools/unix/lsof directory also contains
a more complete list in its mirrors file. Use mirrors with caution -
not all mirrors always have the latest lsof revision.
Some pre-compiled Lsof executables are available on lsof.itap.pur-
due.edu, but their use is discouraged - it's better that you build your
own from the sources. If you feel you must use a pre-compiled exe-
cutable, please read the cautions that appear in the README files of
netstat(1), ofiles(8L), perl(1), ps(1), readlink(2), setlocale(3),
stat(2), uname(1).
Revision-4.79 LSOF(8)
Man(1) output converted with
man2html