Linux lsof command

Selects the listing of files for processes executing the command that begins with the characters of c. Multiple commands may be specified, using multiple -c options. They are joined in a single ORed set before participating in AND option selection.

If c begins with a '^', then the following characters specify a command name whose processes are to be ignored (excluded).

If c begins and ends with a slash ('/'), the characters between the slashes are interpreted as a regular expression. Shell metacharacters in the regular expression must be quoted to prevent their interpretation by the shell. The closing slash may be followed by these modifiers:

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.

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.

Causes lsof to search for all open instances of directory s and the files and directories it contains at its top level. +d does NOT descend the directory tree, rooted at s. The +D D option can 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 with the system stat function.

Specifies a list of FDs (file descriptors) 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.

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 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 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.

Directs lsof's use of the device cache file. The use of this option is sometimes restricted.

-D must be followed by a function letter; the function letter may optionally be followed by a path name. lsof recognizes these function letters:

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.

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.

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 be 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.

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 is specified.

Exempts the file system whose path name is s from being subjected to kernel function calls that might block. The +e option exempts stat, lstat and most readlink kernel function calls. The -e option exempts only stat and lstat kernel function calls. Multiple file systems may be specified with separate +|-e specifications and each may have readlink calls exempted or not.

This option is currently implemented only for Linux.

CAUTION: this option can easily be misapplied to other than the file system of interest, because it uses path name rather than the more reliable device and inode numbers. Device and inode numbers are acquired via the potentially blocking stat kernel call and are thus not available, but see the +|-m m option as a possible alternative way to supply device numbers. Use this option with great care and fully specify the path name of the file system to be exempted.

When open files on exempted file systems are reported, it may not be possible to obtain all their information. Therefore, some information columns will be blank, the characters "UNKN" preface the values in the TYPE column, and the applicable exemption option is added in parentheses to the end of the NAME column. Some device number information might be made available via the +|-m m option.

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 directory name reported by mount, 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 (the mounted device) isn't a block device. This happens for some CD-ROM (Compact Disc Read-Only Memory) 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 in whole or part for some dialects — e.g., /proc-based Linux kernels below 2.6.22. When the prefix to f is a plus sign ('+'), these characters request file structure information:

When the prefix is minus ('-') the same characters disable the listing of the indicated values.

File structure addresses, use counts, flags, and node addresses can detect more readily identical 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.

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 NULL (000).

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 NULL terminator character is used.

Other combinations of fields and their associated field terminator character must be set with explicit entries in f.

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 displays a help list of the field identification characters. Escape the '?' character as your shell requires.

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". Note 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 criteria are applied.

The -g option also enables the output display of PGID numbers. When specified without a PGID set that's all it does.

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 is used only if the dialects supports IPv6, as indicated 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 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):

[4|6][protocol][@hostname|hostaddr][:service|port]

IPv6 options are 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 contains "[46]" and "IPv[46]", IPv6 is supported.

IPv4 hostnames and addresses may not be specified if network file selection is limited to IPv6 with -i 6. IPv6 hostnames 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, 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, UDP, and UDPLITE 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:

Selects the listing of tasks of processes, on dialects where task reporting is supported. If help output — i.e., the output of the -h or -? options — shows this option, then task reporting is supported by the dialect.

When -K and -a are both specified and the tasks of a main process are selected by other options, the main process is also listed as though it were a task, but without a task ID.

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 are listed. When -L is specified (the default), no link counts are listed.

When +L is followed by a number, only files having a link count less than that number are listed (no number may follow -L). A specification of the form "+L1" selects open files that were unlinked. A specification of the form "+aL1 <file_system>" selects unlinked open files on the specified file system.

For other link count comparisons, use field output (-F) and a post-processing script or program.

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 or lstat.

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.

Enables (+) or disables (-) the reporting of portmapper registrations for local TCP, UDP and UDPLITE ports, where port mapping is supported.

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, UDP or UDPLITE 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, UDP or UDPLITE port local if it's found in the local part of its containing kernel structure; or if it's located in the foreign part of its containing kernel structure and the local and foreign Internet addresses are the same; or if it's 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.

Portmapper registration reporting is supported only on dialects that have RPC header files. Some Linux distributions with GlibC 2.14 do not have them. When portmapper registration reporting is supported, the -h or -? help output shows the +|-M 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 for particular kinds of files (e.g., socket files).

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.

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. -o o 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 be 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.

Directs lsof to bypass the strategy it uses to avoid being blocked by some kernel operations — i.e., doing them in forked child processes.

While use of this option reduces lsof startup overhead, it may also cause lsof to hang when the kernel doesn't respond to a function. Use this option cautiously.

Excludes or selects the listing of files for the processes whose optional PID (Process IDentification) 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 selection. However, PID exclusions are applied without ORing or ANDing and take effect before other selection criteria are applied.

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 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 is specified), the default marker is 'm'; otherwise the default marker is "========". The marker is followed by an NL character.

The optional "m<fmt>" argument specifies a format for the marker line. The <fmt> characters following 'm' are interpreted as a format specification to the strftime function, when both it and the localtime function are available in the dialect's C library. Consult the strftime documentation for what may appear in its format specification. Note that when field output is requested with the -F option, <fmt> cannot contain the NL format, "%n". Note also that when <fmt> contains spaces or other characters that affect the shell's interpretation of arguments, <fmt> must be quoted appropriately.

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.

s alone 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.

When followed by a protocol name (p), either TCP or UDP, a colon (':') and a comma-separated protocol state name list, the option causes open TCP and UDP files to be excluded if their state name(s) are in the list (s) preceded by a '^'; or included if their name(s) are not preceded by a '^'.

When an inclusion list is defined, only network files with state names in the list will be present in the lsof output. Thus, specifying one state name means that only network files with that lone state name are listed.

Case is unimportant in the protocol or state names, but there may be no spaces and the colon (':') separating the protocol name (p) and the state name list (s) is required.

If only TCP and UDP files are to be listed, as controlled by the specified exclusions and inclusions, the -i option must be specified, too. If only a single protocol's files are to be listed, add its name as an argument to the -i option.

For example, to list only network files with TCP state LISTEN, use:

-iTCP -sTCP:LISTEN

Or, for example, to list network files with all UDP states except Idle, use:

-iUDP -sUDP:Idle

State names vary with UNIX dialects, so it's not possible to provide a complete list. Some common TCP state names are: CLOSED, IDLE, BOUND, LISTEN, ESTABLISHED, SYN_SENT, SYN_RCDV, ESTABLISHED, CLOSE_WAIT, FIN_WAIT1, CLOSING, LAST_ACK, FIN_WAIT_2, and TIME_WAIT. Two common UDP state names are Unbound and Idle.

The -o (without a following decimal digit count) and -s option (without a following protocol and state name list) 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.

Controls the reporting of some TCP/TPI information, also reported by netstat, following the network addresses. In normal output the information appears in parentheses, each item except TCP (Transmission Control Protocol) or TPI state name 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:

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 shows what selections are 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 — 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 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 follows an '=' and the name -- e.g., "SO=LINGER=5", "SO=QLIM=5", "TF=MSS=512". The following seven values may be reported:

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 are never 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".

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.

Enables (+) or disables (-) the suppression of warning messages.

The lsof builder may choose to have warning messages disabled or enabled by default. The default warning 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.

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, crossover 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 crossover processing; 'l', symbolic link crossover processing.

The -x option may not be supplied without also supplying a +d or +D option.

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.

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 was done, the -X option does 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 appears 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 was zeroed. Another application process, distinct from lsof, asking the kernel to search the directory — e.g., using open — can cause dir_search() to loop forever, thus hanging the application process.

Linux:

This Linux option requests that lsof skip the reporting of information on all open TCP, UDP and UDPLITE IPv4 and IPv6 files.

This Linux option is most useful when the system has an extremely large number of open TCP, UDP and UDPLITE 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, UDP or UDPLITE socket files.

Solaris 10 and above:

This Solaris 10 and above option requests the reporting of cached paths for files that were deleted — i.e., removed with rm or unlink.

The cached path is followed by the string "(deleted)" to indicate that the path used to open the file was deleted.

Because intervening changes made to the path — i.e., renames with mv or rename — are not recorded in the cached path, what lsof reports is only the path used to open the file was opened, not its possibly different final path.

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 are listed, subject to other conditions specified by other options and arguments.

Specifies how SELinux security contexts are to be handled. It and 'Z' field output character support are inhibited when SELinux is disabled in the running Linux kernel.

Without a following argument — e.g., no Z — the option specifies that security contexts are to be listed in the SECURITY-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 processes 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 are 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.

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 lists 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 output, or match the name of a block device associated with a mounted-on directory name. The +|-f option can 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 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 lists 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 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 can 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 system calls. When those conditions are met, lsof can search for the UNIX domain socket when some path to it 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 lists 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.

Multiple file names are joined in a single ORed set before participating in AND option selection.

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.

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.

is the task IDentification number, if a task reporting is supported by the dialect and a task is being listed. If help output — i.e., the output of the -h or -? options — shows this option, then task reporting is supported by the dialect.

A blank TID column indicates a process — i.e., a non-task.

is the File Descriptor number of the file or:

FD is followed by one of these characters, describing the mode under which the file is open:

The mode character is followed by one of these lock characters, describing the type of lock applied to the file:

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 was 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 is specified to +f;

For dialects that support a "namefs" file system, allowing one file to be attached to another with fattach, lsof adds "(FA:<address1><direction><address2>)" to the NAME column. <address1> and <address2> are hexadecimal vnode addresses. <direction> will be "<-" if <address2> was fattach'ed to this vnode whose address is <address1>; and "->" if <address1>, the vnode address of this vnode was 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 was specified and lsof detects the open file's path name was deleted.

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 lowercase — i.e., 'r', 'w', or 'x' — rather than the uppercase 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 an NL (012) (or a NULL (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 identifier 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 identify the command, the process group IDentification (PGID) number, the task 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 NULL (000) field terminator is selected with the 0 (zero) field identifier character, lsof ends each process and file set with an 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 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 NULL terminators). For compatibility reasons neither -F nor -F0 select the raw device field.

These are the fields that lsof produces. The single character listed first is the field identifier.

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 shows what TCP/TPI reporting can be requested.