1. Check the local system version
[root@node ~]# cat /etc/os-release
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"
CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"
2. cp command help
[root@node ~]# cp --help
Usage: cp [OPTION]... [-T] SOURCE DEST
or: cp [OPTION]... SOURCE... DIRECTORY
or: cp [OPTION]... -t DIRECTORY SOURCE...
Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
Mandatory arguments to long options are mandatory for short options too.
-a, --archive same as -dR --preserve=all
--attributes-only don't copy the file data, just the attributes
--backup[=CONTROL] make a backup of each existing destination file
-b like --backup but does not accept an argument
--copy-contents copy contents of special files when recursive
-d same as --no-dereference --preserve=links
-f, --force if an existing destination file cannot be
opened, remove it and try again (this option
is ignored when the -n option is also used)
-i, --interactive prompt before overwrite (overrides a previous -n
option)
-H follow command-line symbolic links in SOURCE
-l, --link hard link files instead of copying
-L, --dereference always follow symbolic links in SOURCE
-n, --no-clobber do not overwrite an existing file (overrides
a previous -i option)
-P, --no-dereference never follow symbolic links in SOURCE
-p same as --preserve=mode,ownership,timestamps
--preserve[=ATTR_LIST] preserve the specified attributes (default:
mode,ownership,timestamps), if possible
additional attributes: context, links, xattr,
all
-c deprecated, same as --preserve=context
--no-preserve=ATTR_LIST don't preserve the specified attributes
--parents use full source file name under DIRECTORY
-R, -r, --recursive copy directories recursively
--reflink[=WHEN] control clone/CoW copies. See below
--remove-destination remove each existing destination file before
attempting to open it (contrast with --force)
--sparse=WHEN control creation of sparse files. See below
--strip-trailing-slashes remove any trailing slashes from each SOURCE
argument
-s, --symbolic-link make symbolic links instead of copying
-S, --suffix=SUFFIX override the usual backup suffix
-t, --target-directory=DIRECTORY copy all SOURCE arguments into DIRECTORY
-T, --no-target-directory treat DEST as a normal file
-u, --update copy only when the SOURCE file is newer
than the destination file or when the
destination file is missing
-v, --verbose explain what is being done
-x, --one-file-system stay on this file system
-Z set SELinux security context of destination
file to default type
--context[=CTX] like -Z, or if CTX is specified then set the
SELinux or SMACK security context to CTX
--help display this help and exit
--version output version information and exit
By default, sparse SOURCE files are detected by a crude heuristic and the
corresponding DEST file is made sparse as well. That is the behavior
selected by --sparse=auto. Specify --sparse=always to create a sparse DEST
file whenever the SOURCE file contains a long enough sequence of zero bytes.
Use --sparse=never to inhibit creation of sparse files.
When --reflink[=always] is specified, perform a lightweight copy, where the
data blocks are copied only when modified. If this is not possible the copy
fails, or if --reflink=auto is specified, fall back to a standard copy.
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable. Here are the values:
none, off never make backups (even if --backup is given)
numbered, t make numbered backups
existing, nil numbered if numbered backups exist, simple otherwise
simple, never always make simple backups
As a special case, cp makes a backup of SOURCE when the force and backup
options are given and SOURCE and DEST are the same name for an existing,
regular file.
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
For complete documentation, run: info coreutils 'cp invocation'
3. the basic parameters of the cp command
Parameter description.
-a: This option is usually used when copying directories; it preserves links, file attributes, and copies everything in the directory. Its effect is equal to the dpR parameter combination.
-d: Keeps the link when copying. The link described here is equivalent to a shortcut in Windows.
-f: Overwrites an already existing target file without prompting.
-i: In contrast to the -f option, the user is prompted to confirm whether to overwrite the target file before it is overwritten, and the target file is overwritten when y is answered.
-p: In addition to copying the contents of the file, the modification time and access rights are also copied to the new file.
-r: If the given source file is a directory file, all subdirectories and files under that directory will be copied.
-l: Does not copy the file, just generates the link file.
4.the daily use of the cp command
1. Copy a folder to another folder
[root@node ~]# cp -r /etc/ /test/
[root@node ~]# ll /test/
total 12
drwxrwxrwx. 2 root root 6 Oct 27 13:10 dir01
drwxrwx---. 2 root root 6 Oct 27 13:10 dir02
d------rwx. 2 root root 6 Oct 27 13:10 dir03
drwxr-xr-x 146 root root 8192 Nov 12 22:56 etc
2. Copy the contents of one folder to another folder
[root@node ~]# mkdir /home/{test01,test02}
[root@node ~]# touch /home/test01/file1
[root@node ~]# cp -r /home/test01/* /home/test02/
[root@node ~]# ll /home/test02/
total 0
-rw-r--r-- 1 root root 0 Nov 12 23:02 file1
[root@node ~]#
5. Precautions for the cp command
1. Copy a folder to another folder
The following 4 methods are to transfer the test01/ directory and its recursive subdirectories and files to another folder
cp -r /home/test01 /home/test02
cp -r /home/test01 /home/test02/
cp -r /home/test01/ /home/test02
cp -r /hometest01/ /home/test02/
2. Copy the contents of one folder to another folder
The following two methods are all about copying the contents of one folder to another folder
cp -r /hometest01/* /home/test02/
cp -r /hometest01/* /home/test02
6. Common operations when backing up files
Recursive copying, the copied data will retain the time stamp and other information of the original data (specifically: time stamp + ownership + copy link file attributes instead of the file itself)
[root@node ~]# cp -a /etc/ /backup/
[root@node ~]# ll /backup/
total 12
drwxr-xr-x. 146 root root 8192 Nov 12 14:03 etc
[root@node ~]# ls /backup/etc/