FIND(1P) POSIX Programmer's Manual FIND(1P)
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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} require-
ments).
The find utility shall detect infinite loops; that is, entering a pre-
viously visited directory that is an ancestor of the last file encoun-
tered. 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 sym-
bolic 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 sym-
bolic 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 argument, it shall be interpreted as a decimal
integer optionally preceded by a plus ( '+' ) or minus ( '-' ) sign, as
follows:
+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 file-
name being examined matches pattern using the pattern 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 differ-
ent 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 operand described in
chmod(), and shall be interpreted as follows. To start, a tem-
plate shall be assumed with all file mode bits cleared. An op
symbol of '+' shall set the appropriate mode bits in the tem-
plate; '-' 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 spe-
cial file, character special file, directory, symbolic link,
FIFO, regular file, or socket, respectively.
-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 sub-
tracted 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 initialization 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 semi-
colon or by a plus sign. Only a plus sign that follows an argu-
ment 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 sta-
tus. 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 invo-
cation shall begin after the last pathname in the set is aggregated,
and shall be completed before the find utility exits and before the
first pathname in the next set (if any) is aggregated for this primary,
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 status. 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 behav-
ior is unspecified.
If a utility_name or argument string contains the two characters "{}",
but not just the two characters "{}", it is implementation-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 primary expres-
sion 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 modification 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 pri-
mary 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 pri-
maries -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 stan-
dard 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 Vari-
ables for the precedence of internationalization 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 pat-
tern 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, sin-
gle-byte as opposed to multi-byte characters in arguments), the
behavior of character classes within the pattern matching nota-
tion used for the -n option, and the behavior of character
classes within regular expressions used in the extended regular
expression defined for the yesexpr locale keyword in the LC_MES-
SAGES category.
LC_MESSAGES
Determine the locale for the processing of affirmative responses
that should be used to affect the format and contents of diag-
nostic 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 mes-
sages.
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 number 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 cur-
rent 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 expres-
sion 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 hav-
ing exactly the matching bits set.
The exact format of the interactive prompts is unspecified. Only the
general nature of the contents of prompts are specified because:
* Implementations may desire more descriptive prompts than those used
on historical implementations.
* Since the historical prompt strings do not terminate with <new-
line>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 utilities 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 histor-
ical implementations. There are at least two reasons for this:
1. In both System V and BSD, find only uses st_size in size calcula-
tions 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 sub-
string 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 prob-
lems in managing memory allocation and dealing with multiple occur-
rences 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 pit-
fall 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 confused 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 unex-
pected 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 consis-
tent. 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 -fol-
low 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 characters (especially <new-
line>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 Interpre-
tation 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 regu-
lar files, and a '+' otherwise:
find / -type f -exec echo {} - ';' -o -exec echo {} + ';'
The change invalidates usage like this. Even though the previous stan-
dard stated that this usage would work, in practice many did not sup-
port 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, Copyright (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.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 FIND(1P)
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