mkfs: symlink support

[minix.git] / commands / find / find.1

.\"     $NetBSD: find.1,v 1.66 2007/07/19 07:49:30 daniel Exp $
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.\"     from: @(#)find.1        8.7 (Berkeley) 5/9/95
.\"
.Dd July 19, 2007
.Dt FIND 1
.Os
.Sh NAME
.Nm find
.Nd walk a file hierarchy
.Sh SYNOPSIS
.Nm
.Op Fl H | Fl L | Fl P
.Op Fl dEhsXx
.Ar file
.Op Ar file ...
.Op Ar expression
.Nm
.Op Fl H | Fl L | Fl P
.Op Fl dEhsXx
.Fl f Ar file
.Op Ar file ...
.Op Ar expression
.Sh DESCRIPTION
.Nm
recursively descends the directory tree for each
.Ar file
listed, evaluating an
.Ar expression
(composed of the
.Dq primaries
and
.Dq operands
listed below) in terms
of each file in the tree.
.Pp
The options are as follows:
.Pp
.Bl -tag -width Ds
.It Fl H
The
.Fl H
option causes the file information and file type (see
.Xr stat 2 ) ,
returned for each symbolic link encountered on the command line to be
those of the file referenced by the link, not the link itself.
If the referenced file does not exist, the file information and type will
be for the link itself.
File information of all symbolic links not on the command line is that
of the link itself.
.It Fl L
The
.Fl L
option causes the file information and file type (see
.Xr stat 2 )
returned for each symbolic link to be those of the file referenced by the
link, not the link itself.
If the referenced file does not exist, the file information and type will
be for the link itself.
.It Fl P
The
.Fl P
option causes the file information and file type (see
.Xr stat 2 )
returned for each symbolic link to be those of the link itself.
.It Fl d
The
.Fl d
option causes
.Nm
to perform a depth-first traversal, i.e., directories
are visited in post-order and all entries in a directory will be acted
on before the directory itself.
By default,
.Nm
visits directories in pre-order, i.e., before their contents.
Note, the default is
.Ar not
a breadth-first traversal.
.It Fl E
The
.Fl E
option causes
.Ar regexp
arguments to primaries to be interpreted as extended regular
expressions (see
.Xr re_format 7 ) .
.It Fl f
The
.Fl f
option specifies a file hierarchy for
.Nm
to traverse.
File hierarchies may also be specified as the operands immediately
following the options.
.It Fl h
The
.Fl h
option causes the file information and file type (see
.Xr stat  2  ) ,
returned for each symbolic link to be those of the file referenced by the
link, not the link itself.
If the referenced file does not exist, the file information and type will
be for the link itself.
.It Fl s
The
.Fl s
option causes the entries of each directory to be sorted in
lexicographical order.
Note that the sorting is done only inside of each directory;
files in different directories are not sorted.
Therefore,
.Sq Li a/b
appears before
.Sq Li a.b ,
which is different from
.Dq Li "find ... \&| sort"
order.
.It Fl X
The
.Fl X
option is a modification to permit
.Nm
to be safely used in conjunction with
.Xr xargs 1 .
If a file name contains any of the delimiting characters used by
.Nm xargs ,
a diagnostic message is displayed on standard error, and the file
is skipped.
The delimiting characters include single
.Pq Dq \&'
and double
.Pq Dq \&"
quotes, backslash
.Pq Dq \e ,
space, tab and newline characters.
Alternatively, the
.Ic -print0
or
.Ic -printx
primaries can be used to format the output in a way that
.Nm xargs
can accept.
.It Fl x
The
.Fl x
option restricts the search to the file system containing the
directory specified.
Does not list mount points to other file systems.
.El
.Sh PRIMARIES
.Bl -tag -width Ds
.It Ic -amin Ar n
True if the difference between the file last access time and the time
.Nm
was started, rounded up to the next full minute, is
.Ar n
minutes.
.It Ic -anewer Ar file
True if the current file has a more recent last access time than
.Ar file  .
.It Ic -atime Ar n
True if the difference between the file last access time and the time
.Nm
was started, rounded up to the next full 24-hour period, is
.Ar n
24-hour periods.
.It Ic -cmin Ar n
True if the difference between the time of last change of file status
information and the time
.Nm
was started, rounded up to the next full minute, is
.Ar n
minutes.
.It Ic -cnewer Ar file
True if the current file has a more recent last change time than
.Ar file  .
.It Ic -ctime Ar n
True if the difference between the time of last change of file status
information and the time
.Nm
was started, rounded up to the next full 24-hour period, is
.Ar n
24-hour periods.
.It Ic -delete
Delete found files and/or directories.
Always returns True.
This executes from the current working directory as
.Nm
recurses down the tree.
It will not attempt to delete a filename with a
.Dq \/
character in its pathname relative to
.Dq \.
for security reasons.
Depth-first traversal processing is implied by this option.
This can also be invoked as
.Ic -rm .
.It Ic -empty
True if the current file or directory is empty.
.\" The ".sp" below is probably not the right way to get the desired effect.
.It Ic -exec Ar utility Oo argument ... Oc No ;
.sp -1l
.It Ic -exec Ar utility Oo argument ... Oc No {} +
Execute the specified
.Ar utility
with the specified arguments.
The list of arguments is terminated by
.Dq Li \&;
or
.Dq Li \&+ .
.Ar utility
will be executed from the directory from which
.Nm
was executed.
.Pp
If terminated by a semicolon
.Pq Dq \&; ,
the
.Ar utility
is invoked once per path.
If the string
.Dq {}
appears anywhere in the utility name or the arguments,
it is replaced by the pathname of the current file.
.Pp
If terminated by a plus sign
.Pq Dq \&+ ,
the pathnames for which the
primary is evaluated are aggregated into sets, and
.Ar utility
will be invoked once per set, similar to
.Xr xargs 1 .
If any invocation exits with non-zero exit status, then
.Nm
will eventually do so as well, but this does not cause
.Nm
to exit early.
The string
.Dq {}
must appear, and must appear last.
Each set is limitted to no more than 5,000 pathnames,
and is also limitted such that the invokation of
.Ar utility
does not exceed
.Dv ARG_MAX .
.It Ic -execdir Ar utility Oo argument ... Oc No ;
The
.Ic -execdir
primary is similar to the semicolon-terminated
.Pq Dq \&;
variant of the
.Ic -exec
primary, with the exception that
.Ar utility
will be executed from the directory that holds
the current file.
The filename substituted for the string
.Dq {}
is not qualified.
Set aggregation
.Pq Do \&+ Dc termination
is not supported.
.It Ic -exit Op Ar n
This primary causes
.Nm
to stop traversing the filesystem and exit immediately if a
previous condition was met.
If no value is specified, the exit value will be 0, else
.Ar n .
Note that other primaries will be evaluated and acted upon before exiting.
.It Ic -false
This primary always evaluates to false.
This can be used following a primary that caused the
expression to be true to make the expression to be false.
This can be useful after using a
.Ic -fprint
primary so it can continue to the next expression (using an
.Cm -or
operator, for example).
.It Ic -flags Oo Fl Oc Ns Ar flags
If
.Ar flags
are preceded by a dash
.Pq Dq - ,
this primary evaluates to true
if at least all of the bits in
.Ar flags
are set in the file's flags bits.
If
.Ar flags
are not preceded by a dash, this primary evaluates to true if
the bits in
.Ar flags
exactly match the file's flags bits.
If
.Ar flags
is
.Dq none ,
files with no flags bits set are matched.
(See
.Xr chflags 1
for more information about file flags.)
.It Ic -follow
Follow symbolic links.
.It Ic -fprint Ar filename
This primary always evaluates to true.
This creates
.Ar filename
or overwrites the file if it already exists.
The file is created at startup.
It writes the pathname of the current file to this file, followed
by a newline character.
The file will be empty if no files are matched.
.It Ic -fstype Ar type
True if the file is contained in a file system of type
.Ar type .
The
.Xr sysctl 8
command can be used to find out the types of filesystems
that are available on the system:
.Bd -literal -offset indent
sysctl vfs.generic.fstypes
.Ed
.Pp
In addition, there are two pseudo-types,
.Dq local
and
.Dq rdonly .
The former matches any file system physically mounted on the system where
the
.Nm
is being executed, and the latter matches any file system which is
mounted read-only.
.It Ic -group Ar gname
True if the file belongs to the group
.Ar gname  .
If
.Ar gname
is numeric and there is no such group name, then
.Ar gname
is treated as a group id.
.It Ic -iname Ar pattern
True if the last component of the pathname being examined
matches
.Ar pattern .
Case insensitive.
.It Ic -inum Ar n
True if the file has inode number
.Ar n  .
.It Ic -iregex Ar regexp
True if the path name of the current file matches the case-insensitive
basic regular expression
.Pq see Xr re_format 7
.Ar regexp .
This is a match on the whole path, not a search for the regular expression
within the path.
.It Ic -links Ar n
True if the file has
.Ar n
links.
.It Ic -rm
This is an alias for
.Ic -delete .
.It Ic -ls
This primary always evaluates to true.
The following information for the current file is written to standard output:
its inode number, size in 512-byte blocks, file permissions, number of hard
links, owner, group, size in bytes, last modification time, and pathname.
If the file is a block or character special file, the major and minor numbers
will be displayed instead of the size in bytes.
If the file is a symbolic link, the pathname of the linked-to file will be
displayed preceded by
.Dq -\*[Gt] .
The format is identical to that produced by
.Dq ls -dgils .
.It Ic -maxdepth Ar n
True if the current search depth is less than or equal to what is specified in
.Ar n .
.It Ic -mindepth Ar n
True if the current search depth is at least what is specified in
.Ar n .
.It Ic -mmin Ar n
True if the difference between the file last modification time and the time
.Nm
was started, rounded up to the next full minute, is
.Ar n
minutes.
.It Ic -mtime Ar n
True if the difference between the file last modification time and the time
.Nm
was started, rounded up to the next full 24-hour period, is
.Ar n
24-hour periods.
.It Ic -ok Ar utility Oo argument ... Oc No ;
The
.Ic -ok
primary is similar to the semicolon-terminated
.Pq Dq \&;
variant of the
.Ic -exec
primary, with the exception that
.Nm
requests user affirmation for the execution of the utility by printing
a message to the terminal and reading a response.
If the response is other than
.Dq y ,
the command is not executed and the
.Ar -ok
primary evaluates to false.
Set aggregation
.Pq Do \&+ Dc termination
is not supported.
.It Ic -name Ar pattern
True if the last component of the pathname being examined matches
.Ar pattern  .
Special shell pattern matching characters
.Po
.Dq \&[ ,
.Dq \&] ,
.Dq \&* ,
.Dq \&?
.Pc
may be used as part of
.Ar pattern  .
These characters may be matched explicitly by escaping them with a
backslash
.Pq Dq \e .
.It Ic -newer Ar file
True if the current file has a more recent last modification time than
.Ar file  .
.It Ic -nouser
True if the file belongs to an unknown user.
.It Ic -nogroup
True if the file belongs to an unknown group.
.It Ic -path Ar pattern
True if the pathname being examined matches
.Ar pattern  .
Special shell pattern matching characters
.Po
.Dq \&[ ,
.Dq \&] ,
.Dq \&* ,
and
.Dq \&?
.Pc
may be used as part of
.Ar pattern  .
These characters may be matched explicitly by escaping them with a
backslash
.Pq Dq \e .
Slashes
.Pq Dq /
are treated as normal characters and do not have to be
matched explicitly.
.It Ic -perm Oo Fl Oc Ns Ar mode
The
.Ar mode
may be either symbolic (see
.Xr chmod  1  )
or an octal number.
If the mode is symbolic, a starting value of zero is assumed and the
mode sets or clears permissions without regard to the process' file mode
creation mask.
If the mode is octal, only bits 07777
.Pf ( Dv S_ISUID
|
.Dv S_ISGID
|
.Dv S_ISTXT
|
.Dv S_IRWXU
|
.Dv S_IRWXG
|
.Dv S_IRWXO )
of the file's mode bits participate
in the comparison.
If the mode is preceded by a dash
.Pq Dq - ,
this primary evaluates to true
if at least all of the bits in the mode are set in the file's mode bits.
If the mode is not preceded by a dash, this primary evaluates to true if
the bits in the mode exactly match the file's mode bits.
Note, the first character of a symbolic mode may not be a dash
.Pq Dq - .
.It Ic -print
This primary always evaluates to true.
It prints the pathname of the current file to standard output, followed
by a newline character.
If none of
.Ic -exec ,
.Ic -exit ,
.Ic -fprint ,
.Ic -ls ,
.Ic -ok ,
.Ic -print0 ,
nor
.Ic -printx
is specified, the given expression shall be effectively replaced by
.Cm \&( Ns Ar given\& expression Ns Cm \&)
.Ic -print .
.It Ic -print0
This primary always evaluates to true.
It prints the pathname of the current file to standard output, followed
by a null character.
.It Ic -printx
This primary always evaluates to true.
It prints the pathname of the current file to standard output,
with each space, tab, newline, backslash, dollar sign, and single,
double, or back quotation mark prefixed by a backslash, so the output of
.Nm find
can safely be used as input to
.Nm xargs .
.It Ic -prune
This primary always evaluates to true.
It causes
.Nm
to not descend into the current file.
Note, the
.Ic -prune
primary has no effect if the
.Fl d
option was specified.
.It Ic -regex Ar regexp
True if the path name of the current file matches the case-sensitive
basic regular expression
.Pq see Xr re_format 7
.Ar regexp .
This is a match on the whole path, not a search for the regular expression
within the path.
.It Ic -size Ar n Ns Op Cm c
True if the file's size, rounded up, in 512-byte blocks is
.Ar n  .
If
.Ar n
is followed by a
.Dq c ,
then the primary is true if the file's size is
.Ar n
bytes.
.It Ic -type Ar t
True if the file is of the specified type.
Possible file types are as follows:
.Pp
.Bl -tag -width flag -offset indent -compact
.It Cm b
block special
.It Cm c
character special
.It Cm d
directory
.It Cm f
regular file
.It Cm l
symbolic link
.It Cm p
FIFO
.It Cm s
socket
.It Cm W
whiteout
.It Cm w
whiteout
.El
.Pp
.It Ic -user Ar uname
True if the file belongs to the user
.Ar uname  .
If
.Ar uname
is numeric and there is no such user name, then
.Ar uname
is treated as a user id (and considered a numeric argument).
.It Ic -xdev
This primary always evaluates to true.
It causes find not to descend past directories that have a different
device ID (st_dev, see
.Xr stat 2
S5.6.2 [POSIX.1]).
.El
.Pp
All primaries which take a numeric argument allow the number to be
preceded by a plus sign
.Pq Dq +
or a minus sign
.Pq Dq \- .
A preceding plus sign means
.Dq more than n ,
a preceding minus sign means
.Dq less than n ,
and neither means
.Dq exactly n .
.Sh OPERATORS
The primaries may be combined using the following operators.
The operators are listed in order of decreasing precedence.
.Bl -tag -width (expression)
.It Cm \&( Ar expression Cm \&)
This evaluates to true if the parenthesized expression evaluates to
true.
.Pp
.It Cm \&! Ar expression
This is the unary
.Tn NOT
operator.
It evaluates to true if the expression is false.
.Pp
.It Ar expression Cm -and Ar expression
.It Ar expression expression
The
.Cm -and
operator is the logical
.Tn AND
operator.
As it is implied by the juxtaposition of two expressions it does not
have to be specified.
The expression evaluates to true if both expressions are true.
The second expression is not evaluated if the first expression is false.
.Pp
.It Ar expression Cm -or Ar expression
The
.Cm -or
operator is the logical
.Tn OR
operator.
The expression evaluates to true if either the first or the second expression
is true.
The second expression is not evaluated if the first expression is true.
.El
.Pp
All operands and primaries must be separate arguments to
.Nm  .
Primaries which themselves take arguments expect each argument
to be a separate argument to
.Nm  .
.Sh EXIT STATUS
The
.Nm
utility normally exits 0 on success, and exits with 1 under certain
internal error conditions.
If any invokations of
.Dq Ic -exec Ar ... No +
primaries return non-zero exit-status, then
.Nm
will do so as well.
.Sh EXAMPLES
The following examples are shown as given to the shell:
.Bl -tag -width findx
.It Li "find  /  \e!  -name  \*q*.c\*q  -print"
Print out a list of all the files whose names do not end in
.Dq \&.c .
.It Li "find  /  -newer  ttt  -user  wnj  -print"
Print out a list of all the files owned by user
.Dq wnj
that are newer than the file
.Dq ttt .
.It Li "find  /  \e!  \e(  -newer  ttt  -user  wnj  \e)  -print"
Print out a list of all the files which are not both newer than
.Dq ttt
and owned by
.Dq wnj .
.It Li "find  /  \e(  -newer  ttt  -or  -user wnj  \e)  -print"
Print out a list of all the files that are either owned by
.Dq wnj
or that are newer than
.Dq ttt .
.It Li "find  /  \e(  -newer  ttt  -or  -user wnj  \e)  -exit 1"
Return immediately with a value of 1 if any files are found that are either
owned by
.Dq wnj
or that are newer than
.Dq ttt ,
but do not print them.
.It Li "find  /  \e(  -newer  ttt  -or  -user wnj  \e)  -ls -exit 1"
Same as above, but list the first file matching the criteria before exiting
with a value of 1.
.El
.Sh SEE ALSO
.Xr chflags 1 ,
.Xr chmod 1 ,
.Xr locate 1 ,
.Xr xargs 1 ,
.Xr stat 2 ,
.Xr fts 3 ,
.Xr getgrent 3 ,
.Xr getpwent 3 ,
.Xr strmode 3 ,
.Xr symlink 7 ,
.Xr sysctl 8
.Sh STANDARDS
The
.Nm
utility syntax is a superset of the syntax specified by the
.St -p1003.2
standard.
.Pp
The options and the
.Ic -amin ,
.Ic -anewer ,
.Ic -cmin ,
.Ic -cnewer ,
.Ic -delete ,
.Ic -empty ,
.Ic -execdir ,
.Ic -follow ,
.Ic -fstype ,
.Ic -iname ,
.Ic -inum ,
.Ic -iregex ,
.Ic -links ,
.Ic -ls ,
.Ic -maxdepth ,
.Ic -mindepth ,
.Ic -mmin ,
.Ic -path ,
.Ic -print0 ,
.Ic -printx ,
.Ic -regex ,
and
.Ic -rm
primaries are extensions to
.St -p1003.2 .
.Pp
Historically, the
.Fl d ,
.Fl h ,
and
.Fl x
options were implemented using the primaries
.Dq -depth ,
.Dq -follow ,
and
.Dq -xdev .
These primaries always evaluated to true.
As they were really global variables that took effect before the traversal
began, some legal expressions could have unexpected results.
An example is the expression
.Dq -print -o -depth .
As -print always evaluates to true, the standard order of evaluation
implies that -depth would never be evaluated.
This is not the case.
.Pp
The operator
.Dq -or
was implemented as
.Dq -o ,
and the operator
.Dq -and
was implemented as
.Dq -a .
.Pp
Historic implementations of the
.Ic -exec
and
.Ic -ok
primaries did not replace the string
.Dq {}
in the utility name or the
utility arguments if it had preceding or following non-whitespace characters.
This version replaces it no matter where in the utility name or arguments
it appears.
.Pp
Support for
.Dq Ic -exec Ar ... No +
is consistent with
.Em IEEE PASC Interpretation 1003.2 #210 ,
though the feature originated in
.Tn SVR4 .
.Pp
The
.Ic -delete
primary does not interact well with other options that cause the filesystem
tree traversal options to be changed.
.Sh HISTORY
A much simpler
.Nm find
command appeared in First Edition AT\*[Am]T Unix.
The syntax had become similar to the present version by
the time of the Fifth Edition.
.Sh BUGS
The special characters used by
.Nm
are also special characters to many shell programs.
In particular, the characters
.Dq \&* ,
.Dq \&[ ,
.Dq \&] ,
.Dq \&? ,
.Dq \&( ,
.Dq \&) ,
.Dq \&! ,
.Dq \e ,
and
.Dq \&;
may have to be escaped from the shell.
.Pp
As there is no delimiter separating options and file names or file
names and the
.Ar expression ,
it is difficult to specify files named
.Dq -xdev
or
.Dq \&! .
These problems are handled by the
.Fl f
option and the
.Xr getopt 3
.Dq --
construct.