| The cp
(copy) command is used to copy files and directories. We will focus on
copying files in this first section. Copying files is a normal
occurrence when working with the file system. A common use of the copy
command is to make a backup of an existing file for safekeeping so
the original can be modified.
Files can be copied two different ways:
- A new file can be created with a
different name in the same directory.
- Files can be copied to a different
location in the directory hierarchy with the same or different
name. They can also be copied to a different disk such as a floppy
or to a centralized server.
The command format below shows two
different formats of the copy command depending on your goal.
Copying Files Within A
Directory
If you wish to copy a file to another file name within the same
directory, use the format in Figure .
The format in Figure
will copy from an existing filename (source_file) to a new file
name (destination_file) in the same directory.
Note: You cannot have two
files of the same name in one directory.
This method of copying files can be
thought of as copying from OLD to NEW in the same
directory. Figure
illustrates copying a file within a directory.
Copying Files to Another Directory
If you wish to copy one or more files to another directory, use the
format in Figure .
The format in Figure
copies the existing file(s) (what you want to copy) to another
directory in the directory structure (where you want to copy it to).
When copying a file this way, it will normally have the same name. You
can add a slash and a file name after the destination directory to
give the file a different name if desired. This version can be thought of
as copying WHAT to WHERE. Figure
shows copying several files using this format. The cp
command assumes the last entry (dir1) is a directory name and the two
prior entries (feathers and feathers_6) are files.
Note: If a file is copied and
the name of the destination directory does not exist, a new file is
created with that name, otherwise the file is copied to the
directory specified.
The copy command can also be used with
metacharacters or wildcards such as the asterisk (*) and question mark
(?) to copy groups of files at the same time. Figure
also shows the use of the asterisk to copy the same files using an
alternative command line.
Preventing Overwriting of Files
If you copy a file and the target name already exists, you will
overwrite or "clobber" the file and will not receive a
warning. To prevent overwriting an existing file when copying, use cp
-i (interactive) option as a
security measure. The -i option only prompts you if you are
about to overwrite an existing file and gives you a choice. Answering
"y" will overwrite the file; answering "n" will
return the shell prompt without copying. It is a good idea
to get into the habit of using cp
-i since it can prevent
accidental mistakes. Figure
shows an example of the cp -i
command.
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