копировать файлы (copy files)
Описание (Description)
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.1‐2017, 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.1‐2017 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.1‐2017 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.1‐2017 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.1‐2017, Section 4.5, File Access Permissions), their effect
on copies of files is implementation-defined.
