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FIND(1P) POSIX Programmer's Manual FIND(1P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (con-
sult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on
Linux.
NAME
find - find files
SYNOPSIS
find [-H | -L] path ... [operand_expression ...]
DESCRIPTION
The find utility shall recursively descend the directory hierarchy from each file specified by path, evaluating a Boolean
expression composed of the primaries described in the OPERANDS section for each file encountered.
The find utility shall be able to descend to arbitrary depths in a file hierarchy and shall not fail due to path length
limitations (unless a path operand specified by the application exceeds {PATH_MAX} requirements).
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.
OPTIONS
The find utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax
Guidelines.
The following options shall be supported by the implementation:
-H Cause the file information and file type evaluated for each symbolic link encountered on the command line to be
those of the file referenced by the link, and not the link itself. If the referenced file does not exist, the file
information and type shall be for the link itself. File information for all symbolic links not on the command line
shall be that of the link itself.
-L Cause the file information and file type evaluated for each symbolic link to be those of the file referenced by
the link, and not the link itself.
Specifying more than one of the mutually-exclusive options -H and -L shall not be considered an error. The last option
specified shall determine the behavior of the utility.
OPERANDS
The following operands shall be supported:
The path operand is a pathname of a starting point in the directory hierarchy.
The first argument that starts with a '-', or is a '!' or a '(', and all subsequent arguments shall be interpreted as an
expression made up of the following primaries and operators. In the descriptions, wherever n is used as a primary argu-
ment, it shall be interpreted as a decimal integer optionally preceded by a plus ( '+' ) or minus ( '-' ) sign, as fol-
lows:
+n More than n.
n Exactly n.
-n Less than n.
The following primaries shall be supported:
-name pattern
The primary shall evaluate as true if the basename of the filename being examined matches pattern using the pat-
tern matching notation described in Pattern Matching Notation .
-nouser
The primary shall evaluate as true if the file belongs to a user ID for which the getpwuid() function defined in
the System Interfaces volume of IEEE Std 1003.1-2001 (or equivalent) returns NULL.
-nogroup
The primary shall evaluate as true if the file belongs to a group ID for which the getgrgid() function defined in
the System Interfaces volume of IEEE Std 1003.1-2001 (or equivalent) returns NULL.
-xdev The primary shall always evaluate as true; it shall cause find not to continue descending past directories that
have a different device ID ( st_dev, see the stat() function defined in the System Interfaces volume of
IEEE Std 1003.1-2001). If any -xdev primary is specified, it shall apply to the entire expression even if the
-xdev primary would not normally be evaluated.
-prune The primary shall always evaluate as true; it shall cause find not to descend the current pathname if it is a
directory. If the -depth primary is specified, the -prune primary shall have no effect.
-perm [-]mode
The mode argument is used to represent file mode bits. It shall be identical in format to the symbolic_mode oper-
and described in chmod(), and shall be interpreted as follows. To start, a template shall be assumed with all
file mode bits cleared. An op symbol of '+' shall set the appropriate mode bits in the template; '-' shall clear
the appropriate bits; '=' shall set the appropriate mode bits, without regard to the contents of process' file
mode creation mask. The op symbol of '-' cannot be the first character of mode; this avoids ambiguity with the
optional leading hyphen. Since the initial mode is all bits off, there are not any symbolic modes that need to use
'-' as the first character.
If the hyphen is omitted, the primary shall evaluate as true when the file permission bits exactly match the value of the
resulting template.
Otherwise, if mode is prefixed by a hyphen, the primary shall evaluate as true if at least all the bits in the resulting
template are set in the file permission bits.
-perm [-]onum
If the hyphen is omitted, the primary shall evaluate as true when the file permission bits exactly match the value
of the octal number onum and only the bits corresponding to the octal mask 07777 shall be compared. (See the
description of the octal mode in chmod().) Otherwise, if onum is prefixed by a hyphen, the primary shall evaluate
as true if at least all of the bits specified in onum that are also set in the octal mask 07777 are set.
-type c
The primary shall evaluate as true if the type of the file is c, where c is 'b', 'c', 'd', 'l', 'p', 'f', or 's'
for block special file, character special file, directory, symbolic link, FIFO, regular file, or socket, respec-
tively.
-links n
The primary shall evaluate as true if the file has n links.
-user uname
The primary shall evaluate as true if the file belongs to the user uname. If uname is a decimal integer and the
getpwnam() (or equivalent) function does not return a valid user name, uname shall be interpreted as a user ID.
-group gname
The primary shall evaluate as true if the file belongs to the group gname. If gname is a decimal integer and the
getgrnam() (or equivalent) function does not return a valid group name, gname shall be interpreted as a group ID.
-size n[c]
The primary shall evaluate as true if the file size in bytes, divided by 512 and rounded up to the next integer,
is n. If n is followed by the character 'c', the size shall be in bytes.
-atime n
The primary shall evaluate as true if the file access time subtracted from the initialization time, divided by
86400 (with any remainder discarded), is n.
-ctime n
The primary shall evaluate as true if the time of last change of file status information subtracted from the ini-
tialization time, divided by 86400 (with any remainder discarded), is n.
-mtime n
The primary shall evaluate as true if the file modification time subtracted from the initialization time, divided
by 86400 (with any remainder discarded), is n.
-exec utility_name [argument ...] ;
-exec utility_name [argument ...]
{} +
The end of the primary expression shall be punctuated by a semicolon or by a plus sign. Only a plus sign that fol-
lows an argument containing the two characters "{}" shall punctuate the end of the primary expression. Other uses
of the plus sign shall not be treated as special.
If the primary expression is punctuated by a semicolon, the utility utility_name shall be invoked once for each pathname
and the primary shall evaluate as true if the utility returns a zero value as exit status. A utility_name or argument
containing only the two characters "{}" shall be replaced by the current pathname.
If the primary expression is punctuated by a plus sign, the primary shall always evaluate as true, and the pathnames for
which the primary is evaluated shall be aggregated into sets. The utility utility_name shall be invoked once for each set
of aggregated pathnames. Each invocation shall begin after the last pathname in the set is aggregated, and shall be com-
pleted before the find utility exits and before the first pathname in the next set (if any) is aggregated for this pri-
mary, but it is otherwise unspecified whether the invocation occurs before, during, or after the evaluations of other
primaries. If any invocation returns a non-zero value as exit status, the find utility shall return a non-zero exit sta-
tus. An argument containing only the two characters "{}" shall be replaced by the set of aggregated pathnames, with each
pathname passed as a separate argument to the invoked utility in the same order that it was aggregated. The size of any
set of two or more pathnames shall be limited such that execution of the utility does not cause the system's {ARG_MAX}
limit to be exceeded. If more than one argument containing only the two characters "{}" is present, the behavior is
unspecified.
If a utility_name or argument string contains the two characters "{}", but not just the two characters "{}", it is imple-
mentation-defined whether find replaces those two characters or uses the string without change. The current directory
for the invocation of utility_name shall be the same as the current directory when the find utility was started. If the
utility_name names any of the special built-in utilities (see Special Built-In Utilities ), the results are undefined.
-ok utility_name [argument ...] ;
The -ok primary shall be equivalent to -exec, except that the use of a plus sign to punctuate the end of the pri-
mary expression need not be supported, and find shall request affirmation of the invocation of utility_name using
the current file as an argument by writing to standard error as described in the STDERR section. If the response
on standard input is affirmative, the utility shall be invoked. Otherwise, the command shall not be invoked and
the value of the -ok operand shall be false.
-print The primary shall always evaluate as true; it shall cause the current pathname to be written to standard output.
-newer file
The primary shall evaluate as true if the modification time of the current file is more recent than the modifica-
tion time of the file named by the pathname file.
-depth The primary shall always evaluate as true; it shall cause descent of the directory hierarchy to be done so that
all entries in a directory are acted on before the directory itself. If a -depth primary is not specified, all
entries in a directory shall be acted on after the directory itself. If any -depth primary is specified, it shall
apply to the entire expression even if the -depth primary would not normally be evaluated.
The primaries can be combined using the following operators (in order of decreasing precedence):
( expression )
True if expression is true.
! expression
Negation of a primary; the unary NOT operator.
expression [-a] expression
Conjunction of primaries; the AND operator is implied by the juxtaposition of two primaries or made explicit by
the optional -a operator. The second expression shall not be evaluated if the first expression is false.
expression -o expression
Alternation of primaries; the OR operator. The second expression shall not be evaluated if the first expression is
true.
If no expression is present, -print shall be used as the expression. Otherwise, if the given expression does not contain
any of the primaries -exec, -ok, or -print, the given expression shall be effectively replaced by:
( given_expression ) -print
The -user, -group, and -newer primaries each shall evaluate their respective arguments only once.
STDIN
If the -ok primary is used, the response shall be read from the standard input. An entire line shall be read as the
response. Otherwise, the standard input shall not be used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of find:
LANG Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions
volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence of international-
ization variables used to determine the values of locale categories.)
LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.
LC_COLLATE
Determine the locale for the behavior of ranges, equivalence classes, and multi-character collating elements used
in the pattern matching notation for the -n option and in the extended regular expression defined for the yesexpr
locale keyword in the LC_MESSAGES category.
LC_CTYPE
This variable determines the locale for the interpretation of sequences of bytes of text data as characters (for
example, single-byte as opposed to multi-byte characters in arguments), the behavior of character classes within
the pattern matching notation used for the -n option, and the behavior of character classes within regular expres-
sions used in the extended regular expression defined for the yesexpr locale keyword in the LC_MESSAGES category.
LC_MESSAGES
Determine the locale for the processing of affirmative responses that should be used to affect the format and con-
tents of diagnostic messages written to standard error.
NLSPATH
Determine the location of message catalogs for the processing of LC_MESSAGES .
PATH Determine the location of the utility_name for the -exec and -ok primaries, as described in the Base Definitions
volume of IEEE Std 1003.1-2001, Chapter 8, Environment Variables.
ASYNCHRONOUS EVENTS
Default.
STDOUT
The -print primary shall cause the current pathnames to be written to standard output. The format shall be:
"%s\n", <path>
STDERR
The -ok primary shall write a prompt to standard error containing at least the utility_name to be invoked and the current
pathname. In the POSIX locale, the last non- <blank> in the prompt shall be '?' . The exact format used is unspecified.
Otherwise, the standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 All path operands were traversed successfully.
>0 An error occurred.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
When used in operands, pattern matching notation, semicolons, opening parentheses, and closing parentheses are special to
the shell and must be quoted (see Quoting ).
The bit that is traditionally used for sticky (historically 01000) is specified in the -perm primary using the octal num-
ber argument form. Since this bit is not defined by this volume of IEEE Std 1003.1-2001, applications must not assume
that it actually refers to the traditional sticky bit.
EXAMPLES
1. The following commands are equivalent:
find .
find . -print
They both write out the entire directory hierarchy from the current directory.
2. The following command:
find / \( -name tmp -o -name '*.xx' \) -atime +7 -exec rm {} \;
removes all files named tmp or ending in .xx that have not been accessed for seven or more 24-hour periods.
3. The following command:
find . -perm -o+w,+s
prints ( -print is assumed) the names of all files in or below the current directory, with all of the file permission
bits S_ISUID, S_ISGID, and S_IWOTH set.
4. The following command:
find . -name SCCS -prune -o -print
recursively prints pathnames of all files in the current directory and below, but skips directories named SCCS and files
in them.
5. The following command:
find . -print -name SCCS -prune
behaves as in the previous example, but prints the names of the SCCS directories.
6. The following command is roughly equivalent to the -nt extension to test:
if [ -n "$(find file1 -prune -newer file2)" ]; then
printf %s\\n "file1 is newer than file2"
fi
7. The descriptions of -atime, -ctime, and -mtime use the terminology n "86400 second periods (days)". For example, a
file accessed at 23:59 is selected by:
find . -atime -1 -print
at 00:01 the next day (less than 24 hours later, not more than one day ago); the midnight boundary between days has no
effect on the 24-hour calculation.
RATIONALE
The -a operator was retained as an optional operator for compatibility with historical shell scripts, even though it is
redundant with expression concatenation.
The descriptions of the '-' modifier on the mode and onum arguments to the -perm primary agree with historical practice
on BSD and System V implementations. System V and BSD documentation both describe it in terms of checking additional
bits; in fact, it uses the same bits, but checks for having at least all of the matching bits set instead of having
exactly the matching bits set.
The exact format of the interactive prompts is unspecified. Only the general nature of the contents of prompts are speci-
fied because:
* Implementations may desire more descriptive prompts than those used on historical implementations.
* Since the historical prompt strings do not terminate with <newline>s, there is no portable way for another program to
interact with the prompts of this utility via pipes.
Therefore, an application using this prompting option relies on the system to provide the most suitable dialog directly
with the user, based on the general guidelines specified.
The -name file operand was changed to use the shell pattern matching notation so that find is consistent with other util-
ities using pattern matching.
The -size operand refers to the size of a file, rather than the number of blocks it may occupy in the file system. The
intent is that the st_size field defined in the System Interfaces volume of IEEE Std 1003.1-2001 should be used, not the
st_blocks found in historical implementations. There are at least two reasons for this:
1. In both System V and BSD, find only uses st_size in size calculations for the operands specified by this volume of
IEEE Std 1003.1-2001. (BSD uses st_blocks only when processing the -ls primary.)
2. Users usually think of file size in terms of bytes, which is also the unit used by the ls utility for the output from
the -l option. (In both System V and BSD, ls uses st_size for the -l option size field and uses st_blocks for the ls
-s calculations. This volume of IEEE Std 1003.1-2001 does not specify ls -s.)
The descriptions of -atime, -ctime, and -mtime were changed from the SVID description of n "days'' to "24-hour periods".
The description is also different in terms of the exact timeframe for the n case (versus the +n or -n), but it matches
all known historical implementations. It refers to one 86400 second period in the past, not any time from the beginning
of that period to the current time. For example, -atime 3 is true if the file was accessed any time in the period from 72
hours to 48 hours ago.
Historical implementations do not modify "{}" when it appears as a substring of an -exec or -ok utility_name or argument
string. There have been numerous user requests for this extension, so this volume of IEEE Std 1003.1-2001 allows the
desired behavior. At least one recent implementation does support this feature, but encountered several problems in man-
aging memory allocation and dealing with multiple occurrences of "{}" in a string while it was being developed, so it is
not yet required behavior.
Assuming the presence of -print was added to correct a historical pitfall that plagues novice users, it is entirely
upwards-compatible from the historical System V find utility. In its simplest form ( find directory), it could be con-
fused with the historical BSD fast find. The BSD developers agreed that adding -print as a default expression was the
correct decision and have added the fast find functionality within a new utility called locate.
Historically, the -L option was implemented using the primary -follow. The -H and -L options were added for two reasons.
First, they offer a finer granularity of control and consistency with other programs that walk file hierarchies. Second,
the -follow primary always evaluated to true. As they were historically really global variables that took effect before
the traversal began, some valid expressions had unexpected results. An example is the expression -print -o -follow.
Because -print always evaluates to true, the standard order of evaluation implies that -follow would never be evaluated.
This was never the case. Historical practice for the -follow primary, however, is not consistent. Some implementations
always follow symbolic links on the command line whether -follow is specified or not. Others follow symbolic links on
the command line only if -follow is specified. Both behaviors are provided by the -H and -L options, but scripts using
the current -follow primary would be broken if the -follow option is specified to work either way.
Since the -L option resolves all symbolic links and the -type l primary is true for symbolic links that still exist after
symbolic links have been resolved, the command:
find -L . -type l
prints a list of symbolic links reachable from the current directory that do not resolve to accessible files.
A feature of SVR4's find utility was the -exec primary's + terminator. This allowed filenames containing special charac-
ters (especially <newline>s) to be grouped together without the problems that occur if such filenames are piped to xargs.
Other implementations have added other ways to get around this problem, notably a -print0 primary that wrote filenames
with a null byte terminator. This was considered here, but not adopted. Using a null terminator meant that any utility
that was going to process find's -print0 output had to add a new option to parse the null terminators it would now be
reading.
The "-exec ... {} +" syntax adopted was a result of IEEE PASC Interpretation 1003.2 #210. It should be noted that this is
an incompatible change to the ISO/IEC 9899:1999 standard. For example, the following command prints all files with a '-'
after their name if they are regular files, and a '+' otherwise:
find / -type f -exec echo {} - ';' -o -exec echo {} + ';'
The change invalidates usage like this. Even though the previous standard stated that this usage would work, in practice
many did not support it and the standard developers felt it better to now state that this was not allowable.
FUTURE DIRECTIONS
None.
SEE ALSO
Quoting, Pattern Matching Notation, Special Built-In Utilities, chmod(), pax, sh, test, the System Interfaces volume of
IEEE Std 1003.1-2001, getgrgid(), getpwuid(), stat()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
Standard is the referee document. The original Standard can be obtained online at http://www.open-
group.org/unix/online.html .
IEEE/The Open Group 2003 FIND(1P)
