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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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CP(1P) POSIX Programmer's Manual CP(1P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
cp — copy files
cp [−Pfip] source_file target_file
cp [−Pfip] source_file... target
cp −R [−H|−L|−P] [−fip] source_file... target
The first synopsis form is denoted by two operands, neither of which
are existing files of type directory. The cp utility shall copy the
contents of source_file (or, if source_file is a file of type
symbolic link, the contents of the file referenced by source_file) to
the destination path named by target_file.
The second synopsis form is denoted by two or more operands where the
−R option is not specified and the first synopsis form is not
applicable. It shall be an error if any source_file is a file of type
directory, if target does not exist, or if target does not name a
directory. The cp utility shall copy the contents of each source_file
(or, if source_file is a file of type symbolic link, the contents of
the file referenced by source_file) to the destination path named by
the concatenation of target, a single <slash> character if target did
not end in a <slash>, and the last component of source_file.
The third synopsis form is denoted by two or more operands where the
−R option is specified. The cp utility shall copy each file in the
file hierarchy rooted in each source_file to a destination path named
as follows:
* If target exists and names an existing directory, the name of the
corresponding destination path for each file in the file
hierarchy shall be the concatenation of target, a single <slash>
character if target did not end in a <slash>, and the pathname of
the file relative to the directory containing source_file.
* If target does not exist and two operands are specified, the name
of the corresponding destination path for source_file shall be
target; the name of the corresponding destination path for all
other files in the file hierarchy shall be the concatenation of
target, a <slash> character, and the pathname of the file
relative to source_file.
It shall be an error if target does not exist and more than two
operands are specified, or if target exists and does not name a
directory.
In the following description, the term dest_file refers to the file
named by the destination path. The term source_file refers to the
file that is being copied, whether specified as an operand or a file
in a file hierarchy rooted in a source_file operand. If source_file
is a file of type symbolic link:
* If the −R option was not specified, cp shall take actions based
on the type and contents of the file referenced by the symbolic
link, and not by the symbolic link itself, unless the −P option
was specified.
* If the −R option was specified:
-- If none of the options −H, −L, nor −P were specified, it is
unspecified which of −H, −L, or −P will be used as a default.
-- If the −H option was specified, cp shall take actions based
on the type and contents of the file referenced by any
symbolic link specified as a source_file operand.
-- If the −L option was specified, cp shall take actions based
on the type and contents of the file referenced by any
symbolic link specified as a source_file operand or any
symbolic links encountered during traversal of a file
hierarchy.
-- If the −P option was specified, cp shall copy any symbolic
link specified as a source_file operand and any symbolic
links encountered during traversal of a file hierarchy, and
shall not follow any symbolic links.
For each source_file, the following steps shall be taken:
1. If source_file references the same file as dest_file, cp may
write a diagnostic message to standard error; it shall do nothing
more with source_file and shall go on to any remaining files.
2. If source_file is of type directory, the following steps shall be
taken:
a. If the −R option was not specified, cp shall write a
diagnostic message to standard error, do nothing more with
source_file, and go on to any remaining files.
b. If source_file was not specified as an operand and
source_file is dot or dot-dot, cp shall do nothing more with
source_file and go on to any remaining files.
c. If dest_file exists and it is a file type not specified by
the System Interfaces volume of POSIX.1‐2008, the behavior is
implementation-defined.
d. If dest_file exists and it is not of type directory, cp shall
write a diagnostic message to standard error, do nothing more
with source_file or any files below source_file in the file
hierarchy, and go on to any remaining files.
e. If the directory dest_file does not exist, it shall be
created with file permission bits set to the same value as
those of source_file, modified by the file creation mask of
the user if the −p option was not specified, and then
bitwise-inclusively OR'ed with S_IRWXU. If dest_file cannot
be created, cp shall write a diagnostic message to standard
error, do nothing more with source_file, and go on to any
remaining files. It is unspecified if cp attempts to copy
files in the file hierarchy rooted in source_file.
f. The files in the directory source_file shall be copied to the
directory dest_file, taking the four steps (1 to 4) listed
here with the files as source_files.
g. If dest_file was created, its file permission bits shall be
changed (if necessary) to be the same as those of
source_file, modified by the file creation mask of the user
if the −p option was not specified.
h. The cp utility shall do nothing more with source_file and go
on to any remaining files.
3. If source_file is of type regular file, the following steps shall
be taken:
a. The behavior is unspecified if dest_file exists and was
written by a previous step. Otherwise, if dest_file exists,
the following steps shall be taken:
i. If the −i option is in effect, the cp utility shall
write a prompt to the standard error and read a line
from the standard input. If the response is not
affirmative, cp shall do nothing more with source_file
and go on to any remaining files.
ii. A file descriptor for dest_file shall be obtained by
performing actions equivalent to the open() function
defined in the System Interfaces volume of POSIX.1‐2008
called using dest_file as the path argument, and the
bitwise-inclusive OR of O_WRONLY and O_TRUNC as the
oflag argument.
iii. If the attempt to obtain a file descriptor fails and the
−f option is in effect, cp shall attempt to remove the
file by performing actions equivalent to the unlink()
function defined in the System Interfaces volume of
POSIX.1‐2008 called using dest_file as the path
argument. If this attempt succeeds, cp shall continue
with step 3b.
b. If dest_file does not exist, a file descriptor shall be
obtained by performing actions equivalent to the open()
function defined in the System Interfaces volume of
POSIX.1‐2008 called using dest_file as the path argument, and
the bitwise-inclusive OR of O_WRONLY and O_CREAT as the oflag
argument. The file permission bits of source_file shall be
the mode argument.
c. If the attempt to obtain a file descriptor fails, cp shall
write a diagnostic message to standard error, do nothing more
with source_file, and go on to any remaining files.
d. The contents of source_file shall be written to the file
descriptor. Any write errors shall cause cp to write a
diagnostic message to standard error and continue to step 3e.
e. The file descriptor shall be closed.
f. The cp utility shall do nothing more with source_file. If a
write error occurred in step 3d, it is unspecified if cp
continues with any remaining files. If no write error
occurred in step 3d, cp shall go on to any remaining files.
4. Otherwise, the −R option was specified, and the following steps
shall be taken:
a. The dest_file shall be created with the same file type as
source_file.
b. If source_file is a file of type FIFO, the file permission
bits shall be the same as those of source_file, modified by
the file creation mask of the user if the −p option was not
specified. Otherwise, the permissions, owner ID, and group ID
of dest_file are implementation-defined.
If this creation fails for any reason, cp shall write a
diagnostic message to standard error, do nothing more with
source_file, and go on to any remaining files.
c. If source_file is a file of type symbolic link, and the
options require the symbolic link itself to be acted upon,
the pathname contained in dest_file shall be the same as the
pathname contained in source_file.
If this fails for any reason, cp shall write a diagnostic
message to standard error, do nothing more with source_file,
and go on to any remaining files.
If the implementation provides additional or alternate access control
mechanisms (see the Base Definitions volume of POSIX.1‐2008, Section
4.4, File Access Permissions), their effect on copies of files is
implementation-defined.
The cp utility shall conform to the Base Definitions volume of
POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
−f If a file descriptor for a destination file cannot be
obtained, as described in step 3.a.ii., attempt to unlink
the destination file and proceed.
−H Take actions based on the type and contents of the file
referenced by any symbolic link specified as a source_file
operand.
−i Write a prompt to standard error before copying to any
existing non-directory destination file. If the response
from the standard input is affirmative, the copy shall be
attempted; otherwise, it shall not.
−L Take actions based on the type and contents of the file
referenced by any symbolic link specified as a source_file
operand or any symbolic links encountered during traversal
of a file hierarchy.
−P Take actions on any symbolic link specified as a
source_file operand or any symbolic link encountered during
traversal of a file hierarchy.
−p Duplicate the following characteristics of each source file
in the corresponding destination file:
1. The time of last data modification and time of last
access. If this duplication fails for any reason, cp
shall write a diagnostic message to standard error.
2. The user ID and group ID. If this duplication fails for
any reason, it is unspecified whether cp writes a
diagnostic message to standard error.
3. The file permission bits and the S_ISUID and S_ISGID
bits. Other, implementation-defined, bits may be
duplicated as well. If this duplication fails for any
reason, cp shall write a diagnostic message to standard
error.
If the user ID or the group ID cannot be duplicated, the
file permission bits S_ISUID and S_ISGID shall be cleared.
If these bits are present in the source file but are not
duplicated in the destination file, it is unspecified
whether cp writes a diagnostic message to standard error.
The order in which the preceding characteristics are
duplicated is unspecified. The dest_file shall not be
deleted if these characteristics cannot be preserved.
−R Copy file hierarchies.
Specifying more than one of the mutually-exclusive options −H, −L,
and −P shall not be considered an error. The last option specified
shall determine the behavior of the utility.
The following operands shall be supported:
source_file
A pathname of a file to be copied. If a source_file operand
is '−', it shall refer to a file named −; implementations
shall not treat it as meaning standard input.
target_file
A pathname of an existing or nonexistent file, used for the
output when a single file is copied. If a target_file
operand is '−', it shall refer to a file named −;
implementations shall not treat it as meaning standard
output.
target A pathname of a directory to contain the copied files.
The standard input shall be used to read an input line in response to
each prompt specified in the STDERR section. Otherwise, the standard
input shall not be used.
The input files specified as operands may be of any file type.
The following environment variables shall affect the execution of cp:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions
volume of POSIX.1‐2008, Section 8.2, Internationalization
Variables 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 extended regular expression defined for the
yesexpr locale keyword in the LC_MESSAGES category.
LC_CTYPE Determine 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 and input
files) and the behavior of character classes used in the
extended regular expression defined for the yesexpr locale
keyword in the LC_MESSAGES category.
LC_MESSAGES
Determine the locale used to process affirmative responses,
and the locale used to affect the format and contents of
diagnostic messages and prompts written to standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Default.
Not used.
A prompt shall be written to standard error under the conditions
specified in the DESCRIPTION section. The prompt shall contain the
destination pathname, but its format is otherwise unspecified.
Otherwise, the standard error shall be used only for diagnostic
messages.
The output files may be of any type.
None.
The following exit values shall be returned:
0 All files were copied successfully.
>0 An error occurred.
If cp is prematurely terminated by a signal or error, files or file
hierarchies may be only partially copied and files and directories
may have incorrect permissions or access and modification times.
The following sections are informative.
The set-user-ID and set-group-ID bits are explicitly cleared when
files are created. This is to prevent users from creating programs
that are set-user-ID or set-group-ID to them when copying files or to
make set-user-ID or set-group-ID files accessible to new groups of
users. For example, if a file is set-user-ID and the copy has a
different group ID than the source, a new group of users has execute
permission to a set-user-ID program than did previously. In
particular, this is a problem for superusers copying users' trees.
None.
The −i option exists on BSD systems, giving applications and users a
way to avoid accidentally removing files when copying. Although the
4.3 BSD version does not prompt if the standard input is not a
terminal, the standard developers decided that use of −i is a request
for interaction, so when the destination path exists, the utility
takes instructions from whatever responds on standard input.
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. Therefore, an application using the −i
option relies on the system to provide the most suitable dialog
directly with the user, based on the behavior specified.
The −p option is historical practice on BSD systems, duplicating the
time of last data modification and time of last access. This volume
of POSIX.1‐2008 extends it to preserve the user and group IDs, as
well as the file permissions. This requirement has obvious problems
in that the directories are almost certainly modified after being
copied. This volume of POSIX.1‐2008 requires that the modification
times be preserved. The statement that the order in which the
characteristics are duplicated is unspecified is to permit
implementations to provide the maximum amount of security for the
user. Implementations should take into account the obvious security
issues involved in setting the owner, group, and mode in the wrong
order or creating files with an owner, group, or mode different from
the final value.
It is unspecified whether cp writes diagnostic messages when the user
and group IDs cannot be set due to the widespread practice of users
using −p to duplicate some portion of the file characteristics,
indifferent to the duplication of others. Historic implementations
only write diagnostic messages on errors other than [EPERM].
Earlier versions of this standard included support for the −r option
to copy file hierarchies. The −r option is historical practice on BSD
and BSD-derived systems. This option is no longer specified by
POSIX.1‐2008 but may be present in some implementations. The −R
option was added as a close synonym to the −r option, selected for
consistency with all other options in this volume of POSIX.1‐2008
that do recursive directory descent.
The difference between −R and the removed −r option is in the
treatment by cp of file types other than regular and directory. It
was implementation-defined how the − option treated special files to
allow both historical implementations and those that chose to support
−r with the same abilities as −R defined by this volume of
POSIX.1‐2008. The original −r flag, for historic reasons, did not
handle special files any differently from regular files, but always
read the file and copied its contents. This had obvious problems in
the presence of special file types; for example, character devices,
FIFOs, and sockets.
When a failure occurs during the copying of a file hierarchy, cp is
required to attempt to copy files that are on the same level in the
hierarchy or above the file where the failure occurred. It is
unspecified if cp shall attempt to copy files below the file where
the failure occurred (which cannot succeed in any case).
Permissions, owners, and groups of created special file types have
been deliberately left as implementation-defined. This is to allow
systems to satisfy special requirements (for example, allowing users
to create character special devices, but requiring them to be owned
by a certain group). In general, it is strongly suggested that the
permissions, owner, and group be the same as if the user had run the
historical mknod, ln, or other utility to create the file. It is also
probable that additional privileges are required to create block,
character, or other implementation-defined special file types.
Additionally, the −p option explicitly requires that all set-user-ID
and set-group-ID permissions be discarded if any of the owner or
group IDs cannot be set. This is to keep users from unintentionally
giving away special privilege when copying programs.
When creating regular files, historical versions of cp use the mode
of the source file as modified by the file mode creation mask. Other
choices would have been to use the mode of the source file unmodified
by the creation mask or to use the same mode as would be given to a
new file created by the user (plus the execution bits of the source
file) and then modify it by the file mode creation mask. In the
absence of any strong reason to change historic practice, it was in
large part retained.
When creating directories, historical versions of cp use the mode of
the source directory, plus read, write, and search bits for the
owner, as modified by the file mode creation mask. This is done so
that cp can copy trees where the user has read permission, but the
owner does not. A side-effect is that if the file creation mask
denies the owner permissions, cp fails. Also, once the copy is done,
historical versions of cp set the permissions on the created
directory to be the same as the source directory, unmodified by the
file creation mask.
This behavior has been modified so that cp is always able to create
the contents of the directory, regardless of the file creation mask.
After the copy is done, the permissions are set to be the same as the
source directory, as modified by the file creation mask. This latter
change from historical behavior is to prevent users from accidentally
creating directories with permissions beyond those they would
normally set and for consistency with the behavior of cp in creating
files.
It is not a requirement that cp detect attempts to copy a file to
itself; however, implementations are strongly encouraged to do so.
Historical implementations have detected the attempt in most cases.
There are two methods of copying subtrees in this volume of
POSIX.1‐2008. The other method is described as part of the pax
utility (see pax(1p)). Both methods are historical practice. The cp
utility provides a simpler, more intuitive interface, while pax
offers a finer granularity of control. Each provides additional
functionality to the other; in particular, pax maintains the hard-
link structure of the hierarchy, while cp does not. It is the
intention of the standard developers that the results be similar
(using appropriate option combinations in both utilities). The
results are not required to be identical; there seemed insufficient
gain to applications to balance the difficulty of implementations
having to guarantee that the results would be exactly identical.
The wording allowing cp to copy a directory to implementation-defined
file types not specified by the System Interfaces volume of
POSIX.1‐2008 is provided so that implementations supporting symbolic
links are not required to prohibit copying directories to symbolic
links. Other extensions to the System Interfaces volume of
POSIX.1‐2008 file types may need to use this loophole as well.
None.
mv(1p), find(1p), ln(1p), pax(1p)
The Base Definitions volume of POSIX.1‐2008, Section 4.4, File Access
Permissions, Chapter 8, Environment Variables, Section 12.2, Utility
Syntax Guidelines
The System Interfaces volume of POSIX.1‐2008, open(3p), unlink(3p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 CP(1P)
Pages that refer to this page: mv(1p), pax(1p)
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