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linux find指令的完整手册

FIND(1) FIND(1)

NAME
find - search for files in a directory hierarchy

SYNOPSIS
find [-H] [-L] [-P] [-D debugopts] [-Olevel] [path...] [expression]

DESCRIPTION
This manual page documents the GNU version of find. GNU find searches the directory tree rooted at each given file name by evaluating the given expression from left to right, according to the rules of
precedence (see section OPERATORS), until the outcome is known (the left hand side is false for and operations, true for or), at which point find moves on to the next file name.

If you are using find in an environment where security is important (for example if you are using it to search directories that are writable by other users), you should read the "Security Considerations"
chapter of the findutils documentation, which is called Finding Files and comes with findutils. That document also includes a lot more detail and discussion than this manual page, so you may find it a more
useful source of information.

OPTIONS
The -H, -L and -P options control the treatment of symbolic links. Command-line arguments following these are taken to be names of files or directories to be examined, up to the first argument that begins
with ‘-’, or the argument ‘(’ or ‘!’. That argument and any following arguments are taken to be the expression describing what is to be searched for. If no paths are given, the current directory is used.
If no expression is given, the expression -print is used (but you should probably consider using -print0 instead, anyway).

This manual page talks about ‘options’ within the expression list. These options control the behaviour of find but are specified immediately after the last path name. The five ‘real’ options -H, -L, -P, -D
and -O must appear before the first path name, if at all. A double dash -- can also be used to signal that any remaining arguments are not options (though ensuring that all start points begin with either

‘./’ or ‘/’ is generally safer if you use wildcards in the list of start points).

-P Never follow symbolic links. This is the default behaviour. When find examines or prints information a file, and the file is a symbolic link, the information used shall be taken from the properties

of the symbolic link itself.

-L Follow symbolic links. When find examines or prints information about files, the information used shall be taken from the properties of the file to which the link points, not from the link itself

(unless it is a broken symbolic link or find is unable to examine the file to which the link points). Use of this option implies -noleaf. If you later use the -P option, -noleaf will still be in

effect. If -L is in effect and find discovers a symbolic link to a subdirectory during its search, the subdirectory pointed to by the symbolic link will be searched.

When the -L option is in effect, the -type predicate will always match against the type of the file that a symbolic link points to rather than the link itself (unless the symbolic link is broken).

Using -L causes the -lname and -ilname predicates always to return false.

-H Do not follow symbolic links, except while processing the command line arguments. When find examines or prints information about files, the information used shall be taken from the properties of the

symbolic link itself. The only exception to this behaviour is when a file specified on the command line is a symbolic link, and the link can be resolved. For that situation, the information used is

taken from whatever the link points to (that is, the link is followed). The information about the link itself is used as a fallback if the file pointed to by the symbolic link cannot be examined. If

-H is in effect and one of the paths specified on the command line is a symbolic link to a directory, the contents of that directory will be examined (though of course -maxdepth 0 would prevent this).

If more than one of -H, -L and -P is specified, each overrides the others; the last one appearing on the command line takes effect. Since it is the default, the -P option should be considered to be in

effect unless either -H or -L is specified.

GNU find frequently stats files during the processing of the command line itself, before any searching has begun. These options also affect how those arguments are processed. Specifically, there are a num-

ber of tests that compare files listed on the command line against a file we are currently considering. In each case, the file specified on the command line will have been examined and some of its proper-

ties will have been saved. If the named file is in fact a symbolic link, and the -P option is in effect (or if neither -H nor -L were specified), the information used for the comparison will be taken from

the properties of the symbolic link. Otherwise, it will be taken from the properties of the file the link points to. If find cannot follow the link (for example because it has insufficient privileges or

the link points to a nonexistent file) the properties of the link itself will be used.

When the -H or -L options are in effect, any symbolic links listed as the argument of -newer will be dereferenced, and the timestamp will be taken from the file to which the symbolic link points. The same

consideration applies to -newerXY, -anewer and -cnewer.

The -follow option has a similar effect to -L, though it takes effect at the point where it appears (that is, if -L is not used but -follow is, any symbolic links appearing after -follow on the command line

will be dereferenced, and those before it will not).

-D debugoptions

Print diagnostic information; this can be helpful to diagnose problems with why find is not doing what you want. The list of debug options should be comma separated. Compatibility of the debug

options is not guaranteed between releases of findutils. For a complete list of valid debug options, see the output of find -D help. Valid debug options include

help Explain the debugging options

tree Show the expression tree in its original and optimised form.

stat Print messages as files are examined with the stat and lstat system calls. The find program tries to minimise such calls.

opt Prints diagnostic information relating to the optimisation of the expression tree; see the -O option.

rates Prints a summary indicating how often each predicate succeeded or failed.

-Olevel

Enables query optimisation. The find program reorders tests to speed up execution while preserving the overall effect; that is, predicates with side effects are not reordered relative to each other.

The optimisations performed at each optimisation level are as follows.

0 Equivalent to optimisation level 1.

1 This is the default optimisation level and corresponds to the traditional behaviour. Expressions are reordered so that tests based only on the names of files (for example -name and -regex) are

performed first.

2 Any -type or -xtype tests are performed after any tests based only on the names of files, but before any tests that require information from the inode. On many modern versions of Unix, file

types are returned by readdir() and so these predicates are faster to evaluate than predicates which need to stat the file first.

3 At this optimisation level, the full cost-based query optimiser is enabled. The order of tests is modified so that cheap (i.e. fast) tests are performed first and more expensive ones are per-

formed later, if necessary. Within each cost band, predicates are evaluated earlier or later according to whether they are likely to succeed or not. For -o, predicates which are likely to

succeed are evaluated earlier, and for -a, predicates which are likely to fail are evaluated earlier.

The cost-based optimiser has a fixed idea of how likely any given test is to succeed. In some cases the probability takes account of the specific nature of the test (for example, -type f is assumed

to be more likely to succeed than -type c). The cost-based optimiser is currently being evaluated. If it does not actually improve the performance of find, it will be removed again. Conversely,

optimisations that prove to be reliable, robust and effective may be enabled at lower optimisation levels over time. However, the default behaviour (i.e. optimisation level 1) will not be changed in

the 4.3.x release series. The findutils test suite runs all the tests on find at each optimisation level and ensures that the result is the same.

EXPRESSIONS

The expression is made up of options (which affect overall operation rather than the processing of a specific file, and always return true), tests (which return a true or false value), and actions (which

have side effects and return a true or false value), all separated by operators. -and is assumed where the operator is omitted.

If the expression contains no actions other than -prune, -print is performed on all files for which the expression is true.

OPTIONS

All options always return true. Except for -daystart, -follow and -regextype, the options affect all tests, including tests specified before the option. This is because the options are processed when the

command line is parsed, while the tests don’t do anything until files are examined. The -daystart, -follow and -regextype options are different in this respect, and have an effect only on tests which appear

later in the command line. Therefore, for clarity, it is best to place them at the beginning of the expression. A warning is issued if you don’t do this.

-d A synonym for -depth, for compatibility with FreeBSD, NetBSD, MacOS X and OpenBSD.

-daystart

Measure times (for -amin, -atime, -cmin, -ctime, -mmin, and -mtime) from the beginning of today rather than from 24 hours ago. This option only affects tests which appear later on the command line.

-depth Process each directory’s contents before the directory itself. The -delete action also implies -depth.

-follow

Deprecated; use the -L option instead. Dereference symbolic links. Implies -noleaf. The -follow option affects only those tests which appear after it on the command line. Unless the -H or -L

option has been specified, the position of the -follow option changes the behaviour of the -newer predicate; any files listed as the argument of -newer will be dereferenced if they are symbolic links.

The same consideration applies to -newerXY, -anewer and -cnewer. Similarly, the -type predicate will always match against the type of the file that a symbolic link points to rather than the link

itself. Using -follow causes the -lname and -ilname predicates always to return false.

-help, --help

Print a summary of the command-line usage of find and exit.

-ignore_readdir_race

Normally, find will emit an error message when it fails to stat a file. If you give this option and a file is deleted between the time find reads the name of the file from the directory and the time

it tries to stat the file, no error message will be issued. This also applies to files or directories whose names are given on the command line. This option takes effect at the time the command

line is read, which means that you cannot search one part of the filesystem with this option on and part of it with this option off (if you need to do that, you will need to issue two find commands

instead, one with the option and one without it).

-maxdepth levels

Descend at most levels (a non-negative integer) levels of directories below the command line arguments. -maxdepth 0

means only apply the tests and actions to the command line arguments.

-mindepth levels

Do not apply any tests or actions at levels less than levels (a non-negative integer). -mindepth 1 means process all files except the command line arguments.

-mount Don’t descend directories on other filesystems. An alternate name for -xdev, for compatibility with some other versions of find.

-noignore_readdir_race

Turns off the effect of -ignore_readdir_race.

-noleaf

Do not optimize by assuming that directories contain 2 fewer subdirectories than their hard link count. This option is needed when searching filesystems that do not follow the Unix directory-link

convention, such as CD-ROM or MS-DOS filesystems or AFS volume mount points. Each directory on a normal Unix filesystem has at least 2 hard links: its name and its ‘.’ entry. Additionally, its sub-

directories (if any) each have a ‘..’ entry linked to that directory. When find is examining a directory, after it has statted 2 fewer subdirectories than the directory’s link count, it knows that

the rest of the entries in the directory are non-directories (‘leaf’ files in the directory tree). If only the files’ names need to be examined, there is no need to stat them; this gives a signifi-

cant increase in search speed.

-regextype type

Changes the regular expression syntax understood by -regex and -iregex tests which occur later on the command line. Currently-implemented types are emacs (this is the default), posix-awk, posix-

basic, posix-egrep and posix-extended.

-version, --version

Print the find version number and exit.

-warn, -nowarn

Turn warning messages on or off. These warnings apply only to the command line usage, not to any conditions that find might encounter when it searches directories. The default behaviour corresponds

to -warn if standard input is a tty, and to -nowarn otherwise.

-xautofs

Don’t descend directories on autofs filesystems.

-xdev Don’t descend directories on other filesystems.

TESTS

Some tests, for example -newerXY and -samefile, allow comparison between the file currently being examined and some reference file specified on the command line. When these tests are used, the interpreta-

tion of the reference file is determined by the options -H, -L and -P and any previous -follow, but the reference file is only examined once, at the time the command line is parsed. If the reference file

cannot be examined (for example, the stat(2) system call fails for it), an error message is issued, and find exits with a nonzero status.

Numeric arguments can be specified as

+n for greater than n,

-n for less than n,

n for exactly n.

-amin n

File was last accessed n minutes ago.

-anewer file

File was last accessed more recently than file was modified. If file is a symbolic link and the -H option or the -L option is in effect, the access time of the file it points to is always used.

-atime n

File was last accessed n*24 hours ago. When find figures out how many 24-hour periods ago the file was last accessed, any fractional part is ignored, so to match -atime +1, a file has to have been

accessed at least two days ago.

-cmin n

File’s status was last changed n minutes ago.

-cnewer file

File’s status was last changed more recently than file was modified. If file is a symbolic link and the -H option or the -L option is in effect, the status-change time of the file it points to is

always used.

-ctime n

File’s status was last changed n*24 hours ago. See the comments for -atime to understand how rounding affects the interpretation of file status change times.

-empty File is empty and is either a regular file or a directory.

-executable

Matches files which are executable and directories which are searchable (in a file name resolution sense). This takes into account access control lists and other permissions artefacts which the -perm

test ignores. This test makes use of the access(2) system call, and so can be fooled by NFS servers which do UID mapping (or root-squashing), since many systems implement access(2) in the client’s

kernel and so cannot make use of the UID mapping information held on the server. Because this test is based only on the result of the access(2) system call, there is no guarantee that a file for

which this test succeeds can actually be executed.

-false Always false.

-fstype type

File is on a filesystem of type type. The valid filesystem types vary among different versions of Unix; an incomplete list of filesystem types that are accepted on some version of Unix or another is:

ufs, 4.2, 4.3, nfs, tmp, mfs, S51K, S52K. You can use -printf with the %F directive to see the types of your filesystems.

-gid n File’s numeric group ID is n.

-group gname

File belongs to group gname (numeric group ID allowed).

-ilname pattern

Like -lname, but the match is case insensitive. If the -L option or the -follow option is in effect, this test returns false unless the symbolic link is broken.

-iname pattern

Like -name, but the match is case insensitive. For example, the patterns ‘fo*’ and ‘F??’ match the file names ‘Foo’, ‘FOO’, ‘foo’, ‘fOo’, etc. In these patterns, unlike filename expansion by the

shell, an initial ‘.’ can be matched by ‘*’. That is, find -name *bar will match the file ‘.foobar’. Please note that you should quote patterns as a matter of course, otherwise the shell will

expand any wildcard characters in them.

-inum n

File has inode number n. It is normally easier to use the -samefile test instead.

-ipath pattern

Behaves in the same way as -iwholename. This option is deprecated, so please do not use it.

-iregex pattern

Like -regex, but the match is case insensitive.

-iwholename pattern

Like -wholename, but the match is case insensitive.

-links n

File has n links.

-lname pattern

File is a symbolic link whose contents match shell pattern pattern. The metacharacters do not treat ‘/’ or ‘.’ specially. If the -L option or the -follow option is in effect, this test returns false

unless the symbolic link is broken.

-mmin n

File’s data was last modified n minutes ago.

-mtime n

File’s data was last modified n*24 hours ago. See the comments for -atime to understand how rounding affects the interpretation of file modification times.

-name pattern

Base of file name (the path with the leading directories removed) matches shell pattern pattern. The metacharacters (‘*’, ‘?’, and ‘[]’) match a ‘.’ at the start of the base name (this is a change in

findutils-4.2.2; see section STANDARDS CONFORMANCE below). To ignore a directory and the files under it, use -prune; see an example in the description of -path. Braces are not recognised as being

special, despite the fact that some shells including Bash imbue braces with a special meaning in shell patterns. The filename matching is performed with the use of the fnmatch(3) library function.

Don’t forget to enclose the pattern in quotes in order to protect it from expansion by the shell.

-newer file

File was modified more recently than file. If file is a symbolic link and the -H option or the -L option is in effect, the modification time of the file it points to is always used.

-newerXY reference

Compares the timestamp of the current file with reference. The reference argument is normally the name of a file (and one of its timestamps is used for the comparison) but it may also be a string

describing an absolute time. X and Y are placeholders for other letters, and these letters select which time belonging to how reference is used for the comparison.

a The access time of the file reference

B The birth time of the file reference

c The inode status change time of reference

m The modification time of the file reference

t reference is interpreted directly as a time

Some combinations are invalid; for example, it is invalid for X to be t. Some combinations are not implemented on all systems; for example B is not supported on all systems. If an invalid or unsup-

ported combination of XY is specified, a fatal error results. Time specifications are interpreted as for the argument to the -d option of GNU date. If you try to use the birth time of a reference

file, and the birth time cannot be determined, a fatal error message results. If you specify a test which refers to the birth time of files being examined, this test will fail for any files where the

birth time is unknown.

-nogroup

No group corresponds to file’s numeric group ID.

-nouser

No user corresponds to file’s numeric user ID.

-path pattern

File name matches shell pattern pattern. The metacharacters do not treat ‘/’ or ‘.’ specially; so, for example,

find . -path "./sr*sc"

will print an entry for a directory called ‘./src/misc’ (if one exists). To ignore a whole directory tree, use -prune rather than checking every file in the tree. For example, to skip the directory

‘src/emacs’ and all files and directories under it, and print the names of the other files found, do something like this:

find . -path ./src/emacs -prune -o -print

Note that the pattern match test applies to the whole file name, starting from one of the start points named on the command line. It would only make sense to use an absolute path name here if the

relevant start point is also an absolute path. This means that this command will never match anything:

find bar -path /foo/bar/myfile -print

The predicate -path is also supported by HP-UX find and will be in a forthcoming version of the POSIX standard.

-perm mode

File’s permission bits are exactly mode (octal or symbolic). Since an exact match is required, if you want to use this form for symbolic modes, you may have to specify a rather complex mode string.

For example ‘-perm g=w’ will only match files which have mode 0020 (that is, ones for which group write permission is the only permission set). It is more likely that you will want to use the ‘/’ or

‘-’ forms, for example ‘-perm -g=w’, which matches any file with group write permission. See the EXAMPLES section for some illustrative examples.

-perm -mode

All of the permission bits mode are set for the file. Symbolic modes are accepted in this form, and this is usually the way in which would want to use them. You must specify ‘u’, ‘g’ or ‘o’ if you

use a symbolic mode. See the EXAMPLES section for some illustrative examples.

-perm /mode

Any of the permission bits mode are set for the file. Symbolic modes are accepted in this form. You must specify ‘u’, ‘g’ or ‘o’ if you use a symbolic mode. See the EXAMPLES section for some illus-

trative examples. If no permission bits in mode are set, this test matches any file (the idea here is to be consistent with the behaviour of -perm -000).

-perm +mode

Deprecated, old way of searching for files with any of the permission bits in mode set. You should use -perm /mode instead. Trying to use the ‘+’ syntax with symbolic modes will yield surprising

results. For example, ‘+u+x’ is a valid symbolic mode (equivalent to +u,+x, i.e. 0111) and will therefore not be evaluated as -perm +mode but instead as the exact mode specifier -perm mode and so it

matches files with exact permissions 0111 instead of files with any execute bit set. If you found this paragraph confusing, you’re not alone - just use -perm /mode. This form of the -perm test is

deprecated because the POSIX specification requires the interpretation of a leading ‘+’ as being part of a symbolic mode, and so we switched to using ‘/’ instead.

-readable

Matches files which are readable. This takes into account access control lists and other permissions artefacts which the -perm test ignores. This test makes use of the access(2) system call, and so

can be fooled by NFS servers which do UID mapping (or root-squashing), since many systems implement access(2) in the client’s kernel and so cannot make use of the UID mapping information held on the

server.

-regex pattern

File name matches regular expression pattern. This is a match on the whole path, not a search. For example, to match a file named ‘./fubar3’, you can use the regular expression ‘.*bar.’ or ‘.*b.*3’,

but not ‘f.*r3’. The regular expressions understood by find are by default Emacs Regular Expressions, but this can be changed with the -regextype option.

-samefile name

File refers to the same inode as name. When -L is in effect, this can include symbolic links.

-size n[cwbkMG]

File uses n units of space. The following suffixes can be used:

‘b’ for 512-byte blocks (this is the default if no suffix is used)

‘c’ for bytes

‘w’ for two-byte words

‘k’ for Kilobytes (units of 1024 bytes)

‘M’ for Megabytes (units of 1048576 bytes)

‘G’ for Gigabytes (units of 1073741824 bytes)

The size does not count indirect blocks, but it does count blocks in sparse files that are not actually allocated. Bear in mind that the ‘%k’ and ‘%b’ format specifiers of -printf handle sparse files

differently. The ‘b’ suffix always denotes 512-byte blocks and never 1 Kilobyte blocks, which is different to the behaviour of -ls.

-true Always true.

-type c

File is of type c:

b block (buffered) special

c character (unbuffered) special

d directory

p named pipe (FIFO)

f regular file

l symbolic link; this is never true if the -L option or the -follow option is in effect, unless the symbolic link is broken. If you want to search for symbolic links when -L is in effect, use

-xtype.

s socket

D door (Solaris)

-uid n File’s numeric user ID is n.

-used n

File was last accessed n days after its status was last changed.

-user uname

File is owned by user uname (numeric user ID allowed).

-wholename pattern

See -path. This alternative is less portable than -path.

-writable

Matches files which are writable. This takes into account access control lists and other permissions artefacts which the -perm test ignores. This test makes use of the access(2) system call, and so

server.

-xtype c

The same as -type unless the file is a symbolic link. For symbolic links: if the -H or -P option was specified, true if the file is a link to a file of type c; if the -L option has been given, true

if c is ‘l’. In other words, for symbolic links, -xtype checks the type of the file that -type does not check.

-context pattern

(SELinux only) Security context of the file matches glob pattern.

ACTIONS

-delete

Delete files; true if removal succeeded. If the removal failed, an error message is issued. If -delete fails, find’s exit status will be nonzero (when it eventually exits). Use of -delete automati-

cally turns on the ‘-depth’ option.

Warnings: Don’t forget that the find command line is evaluated as an expression, so putting -delete first will make find try to delete everything below the starting points you specified. When testing

a find command line that you later intend to use with -delete, you should explicitly specify -depth in order to avoid later surprises. Because -delete implies -depth, you cannot usefully use -prune

and -delete together.

-exec command ;

Execute command; true if 0 status is returned. All following arguments to find are taken to be arguments to the command until an argument consisting of ‘;’ is encountered. The string ‘{}’ is

replaced by the current file name being processed everywhere it occurs in the arguments to the command, not just in arguments where it is alone, as in some versions of find. Both of these construc-

tions might need to be escaped (with a ‘\’) or quoted to protect them from expansion by the shell. See the EXAMPLES section for examples of the use of the -exec option. The specified command is run

once for each matched file. The command is executed in the starting directory. There are unavoidable security problems surrounding use of the -exec action; you should use the -execdir option

instead.

-exec command {} +

This variant of the -exec action runs the specified command on the selected files, but the command line is built by appending each selected file name at the end; the total number of invocations of the

command will be much less than the number of matched files. The command line is built in much the same way that xargs builds its command lines. Only one instance of ‘{}’ is allowed within the com-

mand. The command is executed in the starting directory.

-execdir command ;

-execdir command {} +

Like -exec, but the specified command is run from the subdirectory containing the matched file, which is not normally the directory in which you started find. This a much more secure method for

invoking commands, as it avoids race conditions during resolution of the paths to the matched files. As with the -exec action, the ‘+’ form of -execdir will build a command line to process more than

one matched file, but any given invocation of command will only list files that exist in the same subdirectory. If you use this option, you must ensure that your $PATH environment variable does not

reference ‘.’; otherwise, an attacker can run any commands they like by leaving an appropriately-named file in a directory in which you will run -execdir. The same applies to having entries in $PATH

which are empty or which are not absolute directory names.

-fls file

True; like -ls but write to file like -fprint. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for information about how unusual charac-

ters in filenames are handled.

-fprint file

True; print the full file name into file file. If file does not exist when find is run, it is created; if it does exist, it is truncated. The file names ‘/dev/stdout’ and ‘/dev/stderr’ are handled

specially; they refer to the standard output and standard error output, respectively. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for

information about how unusual characters in filenames are handled.

-fprint0 file

True; like -print0 but write to file like -fprint. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for information about how unusual

characters in filenames are handled.

-fprintf file format

True; like -printf but write to file like -fprint. The output file is always created, even if the predicate is never matched. See the UNUSUAL FILENAMES section for information about how unusual

characters in filenames are handled.

-ls True; list current file in ls -dils format on standard output. The block counts are of 1K blocks, unless the environment variable POSIXLY_CORRECT is set, in which case 512-byte blocks are used. See

the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-ok command ;

Like -exec but ask the user first. If the user agrees, run the command. Otherwise just return false. If the command is run, its standard input is redirected from /dev/null.

The response to the prompt is matched against a pair of regular expressions to determine if it is an affirmative or negative response. This regular expression is obtained from the system if the

‘POSIXLY_CORRECT’ environment variable is set, or otherwise from find’s message translations. If the system has no suitable definition, find’s own definition will be used. In either case, the

interpretation of the regular expression itself will be affected by the environment variables ’LC_CTYPE’ (character classes) and ’LC_COLLATE’ (character ranges and equivalence classes).

-okdir command ;

Like -execdir but ask the user first in the same way as for -ok. If the user does not agree, just return false. If the command is run, its standard input is redirected from /dev/null.

-print True; print the full file name on the standard output, followed by a newline. If you are piping the output of find into another program and there is the faintest possibility that the files which you

are searching for might contain a newline, then you should seriously consider using the -print0 option instead of -print. See the UNUSUAL FILENAMES section for information about how unusual charac-

ters in filenames are handled.

-print0

True; print the full file name on the standard output, followed by a null character (instead of the newline character that -print uses). This allows file names that contain newlines or other types of

white space to be correctly interpreted by programs that process the find output. This option corresponds to the -0 option of xargs.

-printf format

True; print format on the standard output, interpreting ‘\’ escapes and ‘%’ directives. Field widths and precisions can be specified as with the ‘printf’ C function. Please note that many of the

fields are printed as %s rather than %d, and this may mean that flags don’t work as you might expect. This also means that the ‘-’ flag does work (it forces fields to be left-aligned). Unlike

-print, -printf does not add a newline at the end of the string. The escapes and directives are:

\a Alarm bell.

\b Backspace.

\c Stop printing from this format immediately and flush the output.

\f Form feed.

\n Newline.

\r Carriage return.

\t Horizontal tab.

\v Vertical tab.

\0 ASCII NUL.

\\ A literal backslash (‘\’).

\NNN The character whose ASCII code is NNN (octal).

A ‘\’ character followed by any other character is treated as an ordinary character, so they both are printed.

%% A literal percent sign.

%a File’s last access time in the format returned by the C ‘ctime’ function.

%Ak File’s last access time in the format specified by k, which is either ‘@’ or a directive for the C ‘strftime’ function. The possible values for k are listed below; some of them might not be

available on all systems, due to differences in ‘strftime’ between systems.

@ seconds since Jan. 1, 1970, 00:00 GMT, with fractional part.

Time fields:

H hour (00..23)

I hour (01..12)

k hour ( 0..23)

l hour ( 1..12)

M minute (00..59)

p locale’s AM or PM

r time, 12-hour (hh:mm:ss [AP]M)

S Second (00.00 .. 61.00). There is a fractional part.

T time, 24-hour (hh:mm:ss)

+ Date and time, separated by ‘+’, for example ‘2004-04-28+22:22:05.0’. This is a GNU extension. The time is given in the current timezone (which may be affected by setting the TZ envi-

ronment variable). The seconds field includes a fractional part.

X locale’s time representation (H:M:S)

Z time zone (e.g., EDT), or nothing if no time zone is determinable

Date fields:

a locale’s abbreviated weekday name (Sun..Sat)

A locale’s full weekday name, variable length (Sunday..Saturday)

b locale’s abbreviated month name (Jan..Dec)

B locale’s full month name, variable length (January..December)

c locale’s date and time (Sat Nov 04 12:02:33 EST 1989). The format is the same as for ctime(3) and so to preserve compatibility with that format, there is no fractional part in the sec-

onds field.

d day of month (01..31)

D date (mm/dd/yy)

h same as b

j day of year (001..366)

m month (01..12)

U week number of year with Sunday as first day of week (00..53)

w day of week (0..6)

W week number of year with Monday as first day of week (00..53)

x locale’s date representation (mm/dd/yy)

y last two digits of year (00..99)

Y year (1970...)

%b The amount of disk space used for this file in 512-byte blocks. Since disk space is allocated in multiples of the filesystem block size this is usually greater than %s/512, but it can also be

smaller if the file is a sparse file.

%c File’s last status change time in the format returned by the C ‘ctime’ function.

%Ck File’s last status change time in the format specified by k, which is the same as for %A.

%d File’s depth in the directory tree; 0 means the file is a command line argument.

%D The device number on which the file exists (the st_dev field of struct stat), in decimal.

%f File’s name with any leading directories removed (only the last element).

%F Type of the filesystem the file is on; this value can be used for -fstype.

%g File’s group name, or numeric group ID if the group has no name.

%G File’s numeric group ID.

%h Leading directories of file’s name (all but the last element). If the file name contains no slashes (since it is in the current directory) the %h specifier expands to ".".

%H Command line argument under which file was found.

%i File’s inode number (in decimal).

%k The amount of disk space used for this file in 1K blocks. Since disk space is allocated in multiples of the filesystem block size this is usually greater than %s/1024, but it can also be

smaller if the file is a sparse file.

%l Object of symbolic link (empty string if file is not a symbolic link).

%m File’s permission bits (in octal). This option uses the ‘traditional’ numbers which most Unix implementations use, but if your particular implementation uses an unusual ordering of octal per-

missions bits, you will see a difference between the actual value of the file’s mode and the output of %m. Normally you will want to have a leading zero on this number, and to do this, you

should use the # flag (as in, for example, ‘%#m’).

%M File’s permissions (in symbolic form, as for ls). This directive is supported in findutils 4.2.5 and later.

%n Number of hard links to file.

%p File’s name.

%P File’s name with the name of the command line argument under which it was found removed.

%s File’s size in bytes.

%S File’s sparseness. This is calculated as (BLOCKSIZE*st_blocks / st_size). The exact value you will get for an ordinary file of a certain length is system-dependent. However, normally sparse

files will have values less than 1.0, and files which use indirect blocks may have a value which is greater than 1.0. The value used for BLOCKSIZE is system-dependent, but is usually 512

bytes. If the file size is zero, the value printed is undefined. On systems which lack support for st_blocks, a file’s sparseness is assumed to be 1.0.

%t File’s last modification time in the format returned by the C ‘ctime’ function.

%Tk File’s last modification time in the format specified by k, which is the same as for %A.

%u File’s user name, or numeric user ID if the user has no name.

%U File’s numeric user ID.

%y File’s type (like in ls -l), U=unknown type (shouldn’t happen)

%Y File’s type (like %y), plus follow symlinks: L=loop, N=nonexistent

%Z (SELinux only) file’s security context.

A ‘%’ character followed by any other character is discarded, but the other character is printed (don’t rely on this, as further format characters may be introduced). A ‘%’ at the end of the format

argument causes undefined behaviour since there is no following character. In some locales, it may hide your door keys, while in others it may remove the final page from the novel you are reading.

The %m and %d directives support the # , 0 and + flags, but the other directives do not, even if they print numbers. Numeric directives that do not support these flags include G, U, b, D, k and n.

The ‘-’ format flag is supported and changes the alignment of a field from right-justified (which is the default) to left-justified.

See the UNUSUAL FILENAMES section for information about how unusual characters in filenames are handled.

-prune True; if the file is a directory, do not descend into it. If -depth is given, false; no effect. Because -delete implies -depth, you cannot usefully use -prune and -delete together.

-quit Exit immediately. No child processes will be left running, but no more paths specified on the command line will be processed. For example, find /tmp/foo /tmp/bar -print -quit will print only

/tmp/foo. Any command lines which have been built up with -execdir ... {} + will be invoked before find exits. The exit status may or may not be zero, depending on whether an error has already

occurred.

UNUSUAL FILENAMES

Many of the actions of find result in the printing of data which is under the control of other users. This includes file names, sizes, modification times and so forth. File names are a potential problem

since they can contain any character except ‘\0’ and ‘/’. Unusual characters in file names can do unexpected and often undesirable things to your terminal (for example, changing the settings of your func-

tion keys on some terminals). Unusual characters are handled differently by various actions, as described below.

-print0, -fprint0

Always print the exact filename, unchanged, even if the output is going to a terminal.

-ls, -fls

Unusual characters are always escaped. White space, backslash, and double quote characters are printed using C-style escaping (for example ‘\f’, ‘\"’). Other unusual characters are printed using an

octal escape. Other printable characters (for -ls and -fls these are the characters between octal 041 and 0176) are printed as-is.

-printf, -fprintf

If the output is not going to a terminal, it is printed as-is. Otherwise, the result depends on which directive is in use. The directives %D, %F, %g, %G, %H, %Y, and %y expand to values which are

not under control of files’ owners, and so are printed as-is. The directives %a, %b, %c, %d, %i, %k, %m, %M, %n, %s, %t, %u and %U have values which are under the control of files’ owners but which

cannot be used to send arbitrary data to the terminal, and so these are printed as-is. The directives %f, %h, %l, %p and %P are quoted. This quoting is performed in the same way as for GNU ls. This

is not the same quoting mechanism as the one used for -ls and -fls. If you are able to decide what format to use for the output of find then it is normally better to use ‘\0’ as a terminator than to

use newline, as file names can contain white space and newline characters. The setting of the ‘LC_CTYPE’ environment variable is used to determine which characters need to be quoted.

-print, -fprint

Quoting is handled in the same way as for -printf and -fprintf. If you are using find in a script or in a situation where the matched files might have arbitrary names, you should consider using

-print0 instead of -print.

The -ok and -okdir actions print the current filename as-is. This may change in a future release.

OPERATORS

Listed in order of decreasing precedence:

( expr )

Force precedence. Since parentheses are special to the shell, you will normally need to quote them. Many of the examples in this manual page use backslashes for this purpose: ‘$...$’ instead of

‘(...)’.

! expr True if expr is false. This character will also usually need protection from interpretation by the shell.

-not expr

Same as ! expr, but not POSIX compliant.

expr1 expr2

Two expressions in a row are taken to be joined with an implied "and"; expr2 is not evaluated if expr1 is false.

expr1 -a expr2

Same as expr1 expr2.

expr1 -and expr2

Same as expr1 expr2, but not POSIX compliant.

expr1 -o expr2

Or; expr2 is not evaluated if expr1 is true.

expr1 -or expr2

Same as expr1 -o expr2, but not POSIX compliant.

expr1 , expr2

List; both expr1 and expr2 are always evaluated. The value of expr1 is discarded; the value of the list is the value of expr2. The comma operator can be useful for searching for several different

types of thing, but traversing the filesystem hierarchy only once. The -fprintf action can be used to list the various matched items into several different output files.

STANDARDS CONFORMANCE

For closest compliance to the POSIX standard, you should set the POSIXLY_CORRECT environment variable. The following options are specified in the POSIX standard (IEEE Std 1003.1, 2003 Edition):

-H This option is supported.

-L This option is supported.

-name This option is supported, but POSIX conformance depends on the POSIX conformance of the system’s fnmatch(3) library function. As of findutils-4.2.2, shell metacharacters (‘*’, ‘?’ or ‘[]’ for exam-

ple) will match a leading ‘.’, because IEEE PASC interpretation 126 requires this. This is a change from previous versions of findutils.

-type Supported. POSIX specifies ‘b’, ‘c’, ‘d’, ‘l’, ‘p’, ‘f’ and ‘s’. GNU find also supports ‘D’, representing a Door, where the OS provides these.

-ok Supported. Interpretation of the response is according to the "yes" and "no" patterns selected by setting the ‘LC_MESSAGES’ environment variable. When the ‘POSIXLY_CORRECT’ environment variable is

set, these patterns are taken system’s definition of a positive (yes) or negative (no) response. See the system’s documentation for nl_langinfo(3), in particular YESEXPR and NOEXPR. When

‘POSIXLY_CORRECT’ is not set, the patterns are instead taken from find’s own message catalogue.

-newer Supported. If the file specified is a symbolic link, it is always dereferenced. This is a change from previous behaviour, which used to take the relevant time from the symbolic link; see the HISTORY

section below.

-perm Supported. If the POSIXLY_CORRECT environment variable is not set, some mode arguments (for example +a+x) which are not valid in POSIX are supported for backward-compatibility.

Other predicates

The predicates -atime, -ctime, -depth, -group, -links, -mtime, -nogroup, -nouser, -print, -prune, -size, -user and -xdev ‘-atime’, ‘-ctime’, ‘-depth’, ‘-group’, ‘-links’, ‘-mtime’, ‘-nogroup’,

‘-nouser’, ‘-perm’, ‘-print’, ‘-prune’, ‘-size’, ‘-user’ and ‘-xdev’ are all supported.

The POSIX standard specifies parentheses ‘(’, ‘)’, negation ‘!’ and the ‘and’ and ‘or’ operators ( -a, -o).

All other options, predicates, expressions and so forth are extensions beyond the POSIX standard. Many of these extensions are not unique to GNU find, however.

The POSIX standard requires that find detects loops:

The find utility shall detect infinite loops; that is, entering a previously visited directory that is an ancestor of the last file encountered. When it detects an infinite loop, find shall write a

diagnostic message to standard error and shall either recover its position in the hierarchy or terminate.

GNU find complies with these requirements. The link count of directories which contain entries which are hard links to an ancestor will often be lower than they otherwise should be. This can mean that GNU

find will sometimes optimise away the visiting of a subdirectory which is actually a link to an ancestor. Since find does not actually enter such a subdirectory, it is allowed to avoid emitting a diagnostic

message. Although this behaviour may be somewhat confusing, it is unlikely that anybody actually depends on this behaviour. If the leaf optimisation has been turned off with -noleaf, the directory entry

will always be examined and the diagnostic message will be issued where it is appropriate. Symbolic links cannot be used to create filesystem cycles as such, but if the -L option or the -follow option is in

use, a diagnostic message is issued when find encounters a loop of symbolic links. As with loops containing hard links, the leaf optimisation will often mean that find knows that it doesn’t need to call

stat() or chdir() on the symbolic link, so this diagnostic is frequently not necessary.

The -d option is supported for compatibility with various BSD systems, but you should use the POSIX-compliant option -depth instead.

The POSIXLY_CORRECT environment variable does not affect the behaviour of the -regex or -iregex tests because those tests aren’t specified in the POSIX standard.

ENVIRONMENT VARIABLES

LANG Provides a default value for the internationalization variables that are unset or null.

LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.

LC_COLLATE

The POSIX standard specifies that this variable affects the pattern matching to be used for the -name option. GNU find uses the fnmatch(3) library function, and so support for ‘LC_COLLATE’ depends

on the system library. This variable also affects the interpretation of the response to -ok; while the ‘LC_MESSAGES’ variable selects the actual pattern used to interpret the response to -ok, the

interpretation of any bracket expressions in the pattern will be affected by ‘LC_COLLATE’.

LC_CTYPE

This variable affects the treatment of character classes used in regular expressions and also with the -name test, if the system’s fnmatch(3) library function supports this. This variable also

affects the interpretation of any character classes in the regular expressions used to interpret the response to the prompt issued by -ok. The ‘LC_CTYPE’ environment variable will also affect which

characters are considered to be unprintable when filenames are printed; see the section UNUSUAL FILENAMES.

LC_MESSAGES

Determines the locale to be used for internationalised messages. If the ‘POSIXLY_CORRECT’ environment variable is set, this also determines the interpretation of the response to the prompt made by

the -ok action.

NLSPATH

Determines the location of the internationalisation message catalogues.

PATH Affects the directories which are searched to find the executables invoked by -exec, -execdir, -ok and -okdir.

POSIXLY_CORRECT

Determines the block size used by -ls and -fls. If POSIXLY_CORRECT is set, blocks are units of 512 bytes. Otherwise they are units of 1024 bytes.

Setting this variable also turns off warning messages (that is, implies -nowarn) by default, because POSIX requires that apart from the output for -ok, all messages printed on stderr are diagnostics

and must result in a non-zero exit status.

When POSIXLY_CORRECT is not set, -perm +zzz is treated just like -perm /zzz if +zzz is not a valid symbolic mode. When POSIXLY_CORRECT is set, such constructs are treated as an error.

When POSIXLY_CORRECT is set, the response to the prompt made by the -ok action is interpreted according to the system’s message catalogue, as opposed to according to find’s own message translations.

TZ Affects the time zone used for some of the time-related format directives of -printf and -fprintf.

EXAMPLES

find /tmp -name core -type f -print | xargs /bin/rm -f

Find files named core in or below the directory /tmp and delete them. Note that this will work incorrectly if there are any filenames containing newlines, single or double quotes, or spaces.

find /tmp -name core -type f -print0 | xargs -0 /bin/rm -f

Find files named core in or below the directory /tmp and delete them, processing filenames in such a way that file or directory names containing single or double quotes, spaces or newlines are correctly han-

dled. The -name test comes before the -type test in order to avoid having to call stat(2) on every file.

find . -type f -exec file '{}' \;

Runs ‘file’ on every file in or below the current directory. Notice that the braces are enclosed in single quote marks to protect them from interpretation as shell script punctuation. The semicolon is sim-

ilarly protected by the use of a backslash, though single quotes could have been used in that case also.

find / $ -perm -4000 -fprintf /root/suid.txt '%#m %u %p\n' $ , \

$ -size +100M -fprintf /root/big.txt '%-10s %p\n' $

Traverse the filesystem just once, listing setuid files and directories into /root/suid.txt and large files into /root/big.txt.

find $HOME -mtime 0

Search for files in your home directory which have been modified in the last twenty-four hours. This command works this way because the time since each file was last modified is divided by 24 hours and any

remainder is discarded. That means that to match -mtime 0, a file will have to have a modification in the past which is less than 24 hours ago.

find /sbin /usr/sbin -executable \! -readable -print

Search for files which are executable but not readable.

find . -perm 664

Search for files which have read and write permission for their owner, and group, but which other users can read but not write to. Files which meet these criteria but have other permissions bits set (for

example if someone can execute the file) will not be matched.

find . -perm -664

Search for files which have read and write permission for their owner and group, and which other users can read, without regard to the presence of any extra permission bits (for example the executable bit).

This will match a file which has mode 0777, for example.

find . -perm /222

Search for files which are writable by somebody (their owner, or their group, or anybody else).

find . -perm /220

find . -perm /u+w,g+w

find . -perm /u=w,g=w

All three of these commands do the same thing, but the first one uses the octal representation of the file mode, and the other two use the symbolic form. These commands all search for files which are

writable by either their owner or their group. The files don’t have to be writable by both the owner and group to be matched; either will do.

find . -perm -220

find . -perm -g+w,u+w

Both these commands do the same thing; search for files which are writable by both their owner and their group.

find . -perm -444 -perm /222 ! -perm /111

find . -perm -a+r -perm /a+w ! -perm /a+x

These two commands both search for files that are readable for everybody ( -perm -444 or -perm -a+r), have at least one write bit set ( -perm /222 or -perm /a+w) but are not executable for anybody ( ! -perm

/111 and ! -perm /a+x respectively).

cd /source-dir

find . -name .snapshot -prune -o $ \! -name *~ -print0 $|

cpio -pmd0 /dest-dir

This command copies the contents of /source-dir to /dest-dir, but omits files and directories named .snapshot (and anything in them). It also omits files or directories whose name ends in ~, but not their

contents. The construct -prune -o $ ... -print0 $ is quite common. The idea here is that the expression before -prune matches things which are to be pruned. However, the -prune action itself returns

true, so the following -o ensures that the right hand side is evaluated only for those directories which didn’t get pruned (the contents of the pruned directories are not even visited, so their contents are

irrelevant). The expression on the right hand side of the -o is in parentheses only for clarity. It emphasises that the -print0 action takes place only for things that didn’t have -prune applied to them.

Because the default ‘and’ condition between tests binds more tightly than -o, this is the default anyway, but the parentheses help to show what is going on.

find repo/ -exec test -d {}/.svn -o -d {}/.git -o -d {}/CVS ; \

-print -prune

Given the following directory of projects and their associated SCM administrative directories, perform an efficient search for the projects’ roots:

repo/project1/CVS

repo/gnu/project2/.svn

repo/gnu/project3/.svn

repo/gnu/project3/src/.svn

repo/project4/.git

In this example, -prune prevents unnecessary descent into directories that have already been discovered (for example we do not search project3/src because we already found project3/.svn), but ensures sibling

directories (project2 and project3) are found.

EXIT STATUS

find exits with status 0 if all files are processed successfully, greater than 0 if errors occur. This is deliberately a very broad description, but if the return value is non-zero, you should not rely on

the correctness of the results of find.

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