From Linux Man Pages
lsof - list open files
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] ] [ -- ] [names]
DESCRIPTION
Lsof revision 4.77 lists information about files opened by processes for the following UNIX dialects:
AIX 5.[123]
Apple Darwin 7.x and 8.x for 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, 11.11 and 11.23
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
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
(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 spe-
cific 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 OUTPUT 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 out-
put, 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 specified; 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., specifying the -i option without an address
and the -ufoo option produces a listing of all network files OR files belonging to processes owned by user
``foo. Three exceptions are: 1) the `^' (negated) login name or user ID (UID), specified with the -u option;
2) the `^' (negated) process ID (PID), specified with the -p option; and 3) the `^' (negated) process group ID
(PGID), specified with the -g option. Since they represent exclusions, they are applied without ORing or ANDing
and take effect before any other selection criteria are applied.
The -a option may be used to AND the selections. For example, specifying -a, -U, and -ufoo produces a listing of
only UNIX socket files that belong to processes owned by user ``foo.
Caution: the -a option causes all list selection options to be ANDed; 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 acceptable.
Wherever -a is placed, it causes the ANDing of all selection options.
Items of the same selection set - command names, file descriptors, network addresses, process identifiers, user
identifiers, zone names - 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 rep-
resent the -F and -n options, or it might represent the n field identifier character following 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 mean-
ings 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 explain-
ing 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).
See the BLOCKS AND TIMEOUTS and AVOIDING KERNEL BLOCKS sections for information on using this option.
-c c This option selects the listing of files for processes executing the command that begins with the char-
acters of c. Multiple commands may be specified, using multiple -c options. They are joined in a sin-
gle ORed set before participating in AND option selection.
If c begins and ends with a slash ('/'), the characters between the slashes are interpreted as a regular
expression. Shell meta-characters in the regular expression must be quoted to prevent their interpreta-
tion by the shell. The closing 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 regu-
lar 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 struc-
tures 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 section 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 per-
mission to examine with the system stat(2) function.
-d s This option specifies a list of file descriptors (FDs) to exclude from or include in the output listing.
The file descriptors are specified in the comma-separated set s - e.g., ``cwd,1,3, ``^6,^2. (There
should be no spaces in the set.)
The list is an exclusion list if all entries of the set begin with '^'. It is an inclusion list if no
entry begins with '^'. Mixed lists are not permitted.
A file descriptor number range may be in the set as long as neither member is empty, both members are
numbers, and the 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 directo-
ries 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 per-
mission 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
The b, r, and u functions, accompanied by a path name, are sometimes restricted. When these functions
are restricted, they will not appear in the description of the -D option that accompanies -h or -?
option output. See the DEVICE CACHE FILE section and the sections that follow it for more information
on these functions and when they're restricted.
The ? function reports the read-only and write paths that lsof can use for the device cache file, the
names of any environment variables whose values lsof will examine when forming the device cache file
path, and the format for the personal device cache file path. (Escape the `?' character as your shell
requires.)
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 outdated
device cache file, or creating a new one in its place. The r function is always available when it is
specified without a path name argument; it may be restricted by the permissions 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 interpreted. When followed by c, f, g, G, or n
in any combination it specifies that the listing of kernel file structure information 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.
Be careful to make sure +f and -f are properly terminated and aren't followed by a character (e.g., of
the file or file system name) that might be taken as a parameter. For example, use ``-- after +f and
-f as in these examples.
$ lsof +f -- /file/system/name
$ lsof -f -- /file/name
The listing of information from kernel file structures, requested with the +f [cfgGn] option form, is
normally inhibited, and is not available for some dialects - e.g., /proc-based Linux. When the prefix
to f is a plus sign (`+'), these characters request file structure information:
c file structure use count
f file structure address
g file flag abbreviations
G file flags in hexadecimal
n file structure node address
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 iden-
tical files inherited by child processes and identical files in use by different processes. Lsof column
output can be sorted by output columns holding the values and listed to identify identical 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 speci-
fied 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 charac-
ters and the field output process.
When the field selection character list is empty, all standard fields are selected (except the raw
device field 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 terminator 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 - specification 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.)
-g [s] This option excludes or selects the listing of files for the processes whose optional process group
IDentification (PGID) numbers are in the comma-separated set s - e.g., ``123 or ``123,^456. (There
should be no spaces in the set.)
PGID numbers that begin with `^' (negation) represent exclusions.
Multiple PGID numbers are joined in a single ORed set before participating in AND option selection.
However, PGID exclusions are applied without ORing or ANDing and take effect before other selection cri-
teria are applied.
The -g option also enables the output display of PGID numbers. 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 displayed. (An IPv6 specification may be used only if the dialects supports IPv6, as indi-
cated by ``[46] and ``IPv[46] in lsof's -h or -? output.) Sequentially specifying -i4, followed by
-i6 is the same as specifying -i, and vice-versa. Specifying -i4, or -i6 after -i is the same as speci-
fying -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 participat-
ing 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 specify the -h or -? (help) option. If the displayed description of the -i option con-
tains ``[46] and ``IPv[46], IPv6 is supported.
IPv4 host names and addresses may not be specified if network file selection is limited to IPv6 with -i
6. IPv6 host names and addresses may not be specified if network file selection is limited to IPv4 with
-i 4. When an open IPv4 network file's address is mapped in an IPv6 address, the open file's type will
be IPv6, not IPv4, and its display will be selected by '6', not '4'.
At least one address component - 4, 6, protocol, ,IR hostname , hostaddr, or service - must be supplied.
The `@' character, leading the host specification, is always required; as is the `:', leading the port
specification. Specify either hostname 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 embedded 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 post-processing script or program.
+|-m m This option specifies an alternate kernel memory file or activates mount table supplement processing.
The option form -m m specifies a kernel memory file, m, in place of /dev/kmem or /dev/mem - e.g., a
crash dump file.
The option form +m requests that a mount supplement file be written to the standard output file. All
other options are silently ignored.
There will be a line in the mount supplement file for each mounted file system, containing the mounted
file system directory, followed by a single space, followed by the device number 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 supported 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 registrations 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 distributed 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 displays 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 reporting is slowing or blocking lsof.
For purposes of portmapper registration reporting lsof considers 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 multi-
ple interfaces when the foreign Internet address is on a different interface from the local one.
See the lsof FAQ (The FAQ section gives its location.) for further discussion of portmapper registra-
tion reporting issues.
-n This option inhibits the conversion of network numbers to host names for network files. Inhibiting con-
version may make lsof run faster. It is also useful when host name lookup is not working properly.
-N This option selects the listing of NFS files.
-o This option directs lsof to display file offset at all times. It causes the SIZE/OFF output column
title to be changed to OFFSET. Note: on some UNIX dialects lsof can't obtain accurate 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 whatever 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 off-
set or offset-only output. Thus, for example, to direct lsof to display offset at all times with a dec-
imal 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 ker-
nel 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 IDentifi-
cation (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 exclusions.
Multiple process ID numbers are joined in a single ORed set before participating in AND option selec-
tion. However, PID exclusions are applied without ORing or ANDing and take effect before other selec-
tion criteria are applied.
-P This option inhibits the conversion of port numbers to port names for network files. Inhibiting the
conversion may make lsof run a little faster. It is also useful when port name lookup is not working
properly.
+|-r [t] This option puts lsof in repeat mode. There lsof lists open files as selected by other options, delays
t seconds (default fifteen), then repeats the listing, delaying and listing repetitively until stopped
by a condition defined by the prefix to the option.
If the prefix is a `-', repeat mode is endless. Lsof must be terminated with an interrupt or quit sig-
nal.
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 followed by a NL character.
Repeat mode reduces lsof startup overhead, so it is more efficient to use this mode than to call lsof
repetitively from a shell script, for example.
To use repeat mode most efficiently, accompany +|-r with specification 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 IDentification 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.
-T [t] This option controls the reporting of some TCP/TPI information, also reported by netstat(1), following
the network addresses. In normal output the information appears in parentheses, each item except state
identified by a keyword, followed by `=', separated from others by a single space:
<TCP or TPI state name>
QR=<read queue length>
QS=<send queue length>
SO=<socket options and values>
SS=<socket states>
TF=<TCP flags and values>
WR=<window read length>
WW=<window write length>
Not all values are reported for all UNIX dialects. Items values (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 information 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 meaning of the flags, options, states and val-
ues.
``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)
LINGER linger time (SO_LINGER)
MSS maximum segment size (TCP_MAXSEG)
PQLEN partial listen queue connections
QLEN established listen queue connections
QLIM established listen queue limit
RCVBUF receive buffer length (SO_RCVBUF)
SNDBUF send buffer length (SO_SNDBUF)
Details on what socket options and values, socket states, and TCP flags and values may be displayed for
particular UNIX dialects may be found in the answer to the ``Why doesn't lsof report socket options,
socket states, and TCP flags and values for my dialect? and ``Why doesn't lsof report the partial lis-
ten queue connection count for my dialect? questions in the lsof FAQ (The FAQ section gives its loca-
tion.)
-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 spaces 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 constructed; 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 compile-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 HASNOSOCKSECURITY are defined at compile time and they prevent the listing
of open files.
+|-w Enables (+) or disables (-) the suppression of warning messages.
The lsof builder may choose to have warning messages disabled or enabled by default. The default warn-
ing message state is indicated in the output of the -h or -? option. Disabling warning messages when
they are already disabled or enabling them when already enabled is acceptable.
The -t option selects the -w option.
-x [fl] This option may accompany the +d and +D options to direct their processing to cross over symbolic links
and|or file system mount points encountered when scanning the directory (+d) 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 without 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 processing.
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 per-
form 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 mem-
ory, 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.
Consult the lsof FAQ (The FAQ section gives its location.) and the 00README file of the lsof distribu-
tion for a more complete description of the Stale Segment ID bug, its APAR, and methods for defining
readx() use when compiling lsof.
Linux:
This Linux option requests that lsof skip the reporting of information on all open TCP and UDP IPv4 and
IPv6 files.
This Linux option is most useful when the system has an extremely large number of open TCP and UDP
files, the processing of whose information in the /proc/net/tcp* and /proc/net/udp* files would take
lsof a long time, and whose 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 specifies that zone names are to be listed in the
ZONE output column.
The -z option may be followed by a zone name, z. That causes lsof to list only open files for processes
in that zone. Multiple -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 specified
by other options and arguments.
-- The double minus sign option is a marker that signals the end of the keyed options. It may be used, for
example, when the first file name begins with a minus sign. It may also be used when the absence of a
value for the last keyed option must be signified by the presence of a minus sign in the following
option and before the start of the file names.
names These are path names of specific files to list. Symbolic links are resolved before use. The first name
may be separated from the preceding options with the ``-- option.
If a name is the mounted-on directory of a file system or the device of the file system, lsof will list
all the files open 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 regular file is treated - i.e., its listing is restricted to processes 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 structure. (See the next para-
graph 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 spec-
ify 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 num-
bers 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 information.
Multiple file names are joined in a single ORed set before participating in AND option selection.
AFS
Lsof supports the recognition of AFS files for these dialects (and AFS versions):
AIX 4.1.4 (AFS 3.4a)
HP-UX 9.0.5 (AFS 3.4a)
Linux 1.2.13 (AFS 3.3)
Solaris 2.[56] (AFS 3.4a)
It may recognize AFS files on other versions of these dialects, but has not been tested there. Depending on how
AFS is implemented, lsof may recognize AFS files in other dialects, or may have difficulties recognizing 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 compute 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 information about dynamic modules, their sym-
bols, 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 disabled when lsof is compiled.) Third, its -k and -m options name alternate kernel name list or memory
files.
Restricting the listing of all open files is controlled by the compile-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 HASNOSOCKSE-
CURITY definitions.
See the Security section of the 00README file of the lsof distribution for information on building lsof with the
HASSECURITY and HASNOSOCKSECURITY options enabled.
Creation and use of a user-readable and user-writable device cache file is controlled by the compile-time HASD-
CACHE option. See the DEVICE CACHE FILE section and the sections that follow it for details on how its path is
formed. For security considerations it is important to note that in the default lsof distribution, if the real
user ID under which lsof is executed is root, the device cache file will be written in root's home directory -
e.g., / or /root. When HASDCACHE is not defined, lsof does not write or attempt to read a device cache file.
When HASDCACHE is defined, the lsof help output, presented in response to the -h, -D?, or -? options, will pro-
vide device cache file handling information. When HASDCACHE is not defined, the -h or -? output will have no -D
option description.
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 characters. 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-printable 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 consid-
ered printable 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 characters - 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 loca-
tion.) for more information.
Lsof dynamically sizes the output columns each time it runs, guaranteeing that each column is a minimum size. It
also guarantees that each column is separated from its predecessor by at least one space.
COMMAND contains the first nine characters of the name of the UNIX command associated with the process. If a
non-zero w value is specified to the +c w option, the column contains the first w characters of the
name of the UNIX command associated with the process up to the limit of characters supplied to lsof by
the UNIX dialect. (See the description of the +c w command or the lsof FAQ for more information. The
FAQ section gives its location.)
If w is less than the length of the column title, ``COMMAND, it will be raised to that length.
If a zero w value is specified to the +c w option, the column contains all the characters of the name
of the UNIX command 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.
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 descrip-
tion for information on when a user ID number or login name is displayed.)
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 characters, 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 parsing 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 ``DIR for a directory;
or ``DOOR for a VDOOR file;
or ``FIFO for a FIFO special file;
or ``KQUEUE for a BSD style kernel event queue file;
or ``LINK for a symbolic link file;
or ``MPB for a multiplexed block file;
or ``MPC for a multiplexed character file;
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 ``PLWU for a /proc/lwpusage file;
or ``PLWX for a /proc/xregs file'
or ``PMAP for a /proc map file (map);
or ``PMEM for a /proc memory image file;
or ``PNTF for a /proc process notifier file;
or ``POBJ for a /proc/object file;
or ``PODR for a /proc/object directory;
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;
FCT contains the file reference count from the kernel file structure when c has been specified to +f;
FILE-FLAG when g or G has been specified to +f, this field contains the contents of the f_flag[s] member of the
kernel file structure and the kernel's per-process open file flags (if available); `G' causes them to
be displayed in hexadecimal; `g', as short-hand names; two lists may be displayed with entries sepa-
rated by commas, the lists separated by a semicolon (`;'); the first list may contain short-hand names
for f_flag[s] values from the following table:
AIO asynchronous I/O (e.g., FAIO)
AP append
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
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
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
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
RC file and record locking cache
REV revoked
RSH shared read
RSYN read synchronization
SL shared lock
SNAP cooked snapshot
SOCK socket
SQSH Sequent shared set on open
SQSV Sequent SVM set on open
SQR Sequent set repair on open
SQS1 Sequent full shared open
SQS2 Sequent partial shared open
STPI stop I/O
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 table:
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 identifier 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 example.);
or the base address or device name of a Linux AX.25 socket device.
Usually only the lower thirty two bits of Tru64 UNIX kernel addresses are displayed.
SIZE, SIZE/OFF, or OFFSET
is the size of the file or the file offset in bytes. A value is displayed in this column only if it
is available. Lsof displays whatever value - size or offset - is appropriate for the type of the file
and the version of lsof.
On some UNIX dialects lsof can't obtain accurate or consistent 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 con-
tent 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 normally displayed in decimal with a leading
``0t if it contains 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 avail-
able) 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 descrip-
tion 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 speci-
fied.
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 ker-
nel 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.
NAME is the name of the mount point and file system on which the file resides;
or the name of a file specified in the names option (after any symbolic links have been resolved);
or the name of a character special or block special device;
or the local and remote Internet addresses of a network file; the local host name or IP number is fol-
lowed by a colon (':'), the port, ``->, and the two-part remote address; IP addresses may be
reported as numbers or names, depending on the +|-M, -n, and -P options; colon-separated 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 destination; TCP and UDP remote addresses
may be followed by TCP/TPI information in parentheses - state (e.g., ``(ESTABLISHED),
``(Unbound)), queue sizes, and window sizes (not all dialects) - in a fashion similar to what net-
stat(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 ``rd=<offset> and ``wr=<offset> for the values of the read and write offsets of a FIFO;
or ``clone n:/dev/event for SCO OpenServer file clones of the /dev/event device, where n is the
minor device number of the file;
or ``(socketpair: n) for a Solaris 2.6, 8, 9 or 10 UNIX domain socket, created by the socket-
pair(3N) network function;
or ``no PCB for socket files that do not have a protocol block associated with them, optionally fol-
lowed by ``, CANTSENDMORE if sending on the socket has been disabled, 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>, fol-
lowed 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, fol-
lowed 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 hex-
adecimal 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 omitted 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 questionable 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
information 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.
OUTPUT FOR OTHER PROGRAMS
When the -F option is specified, lsof produces output that is suitable for processing by another program - e.g,
an awk or Perl script, or a C program.
Each unit of information is output in a field that is identified with a leading character and terminated by a NL
(012) (or a NUL (000) if the 0 (zero) field identifier character is specified.) The data of the field follows
immediately after the field identification character and extends to the field terminator.
It is possible to think of field output as process and file sets. A process set begins with a field whose iden-
tifier is `p' (for process 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 iden-
tify the command, 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 - specification 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 sup-
ports 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)
g process group ID
P protocol name
r raw device number (0x<hexadecimal>)
R parent process ID
s file's size (decimal)
S file's stream identification
t file's type
T TCP/TPI information, identified by prefixes (the
`=' is part of the prefix):
QR=<read queue size>
QS=<send queue size>
SO=<socket options and values> (not all dialects)
SS=<socket states> (not all dialects)
ST=<connection state>
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
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 `?' character 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 number 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 speci-
fied to change the field terminator 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 charac-
ters 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 characters, 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 out-
put to validate the correct operation of lsof. The library can be found in the tests/LTlib.c file of the lsof
distribution. The library uses the first aid, the lsof_fields.h header file.
BLOCKS AND TIMEOUTS
Lsof can be blocked by some kernel functions that it uses - lstat(2), readlink(2), and stat(2). These functions
are stalled in the kernel, for example, when the hosts where mounted NFS file systems reside become inaccessible.
Lsof attempts to break these blocks with timers and child processes, but the techniques are not wholly reliable.
When lsof does manage to break a block, it will report the break with an error message. The messages may be sup-
pressed with the -t and -w options.
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 responsiveness
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 specifying 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 alter-
nates, its ability to locate files on file systems depends completely on the availability and accuracy of the
alternates. If no alternates are available, 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) kernel functions, or because you specified the -b option, lsof can obtain some of the
information it needs - the device number and possibly the file system type - from the system mount table. When
that is possible, lsof will report the device number it obtained. (You can suppress the report by specifying the
-w option.)
You can assist this process if your mount table is supported with an /etc/mtab or /etc/mnttab file that contains
an options field by adding a ``dev=xxxx field for mount points that do not have one in their options strings.
Note: you must be able to edit the file - i.e., some mount tables like recent Solaris /etc/mnttab or Linux
/proc/mounts are read-only and can't be modified.
You may also be able to supply device numbers using the +m and +m m 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 sys-
tems.) 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 dis-
play 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 alternative 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.
When lsof is run in repeat mode - i.e., with the -r option specified - the extent to which it can report path
name components for the same file may vary from cycle to cycle. That's because other running processes can cause
the kernel to remove entries from its name cache and replace them with others.
Lsof's use of the kernel name cache to identify the paths of files can lead it to report incorrect components
under some circumstances. This can happen when the kernel name cache uses device and node number as a key (e.g.,
SCO OpenServer) and a key on a rapidly changing file system is reused. If the UNIX dialect's kernel doesn't
purge the name cache entry for a file when it is unlinked, lsof may find a reference to the wrong entry in the
cache. The lsof FAQ (The FAQ section gives its location.) has more information on this situation.
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 sec-
tion 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 envi-
ronment variables, and the personal device cache path format.
Lsof can detect that the current device cache file has been accidentally or maliciously modified by integrity
checks, including the computation 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 legitimately write.
The path from which a lsof process may attempt to read a device cache file may not be the same as the path to
which it can legitimately write. Thus when lsof senses that it needs to update the device cache file, it may
choose a different path for writing it from the path from which it read an incorrect or outdated version.
If available, the -Dr option will inhibit the writing of a new device cache file. (It's always available when
specified without a path name argument.)
When a new device is added to the system, the device cache file may need to be recreated. Since lsof compares
the mtime of the device cache file with the mtime and ctime of the /dev (or /devices) directory, 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 administrator 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 permission after it has accessed the kernel
memory devices. When it does that, lsof can allow more liberal device cache path formations. The lsof distribu-
tion recommends that versions for these dialects run setgid and be allowed to surrender setgid permission.
AIX 5.[123]
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.)
Lsof for these dialects does not support a device cache, so the permissions given to the executable don't apply
to the device cache file.
Linux
DEVICE CACHE FILE PATH FROM THE -D OPTION
The -D option provides limited means for specifying the device cache file path. Its ? function will report the
read-only and write device cache file paths that lsof will use.
When the -D b, r, and u functions are available, you can use them to request that the cache file be built in a
specific location (b[path]); read but not rebuilt (r[path]); or read and rebuilt (u[path]). The b, r, and u
functions are restricted under some conditions. They are 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 imple-
mentations that normally don't surrender their setgid permission.)
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