You can use RSYNC (Remote Sync), a Unix-based command-line tool, to copy and synchronize files/directories in a local or remote system while keeping the existing files intact. It can significantly speed up backup processes by copying only the changes in files. However, to copy files without overwriting, you might want to use particular flags/options with the rsync command.
Below is the general syntax for the rsync command:
```
rsync options source destination
```
To copy files without overwriting, you might use the command as:
```
rsync -av —ignore-existing source_directory/ destination_directory/
```
In the above command, `-a` is for archiving, which preserves the attributes of the files such as timestamps, group, ownership, permissions, etc., and `-v` is for verbose output.
The `—ignore-existing` flag prevents existing files in the destination directory from being overwritten.
Here is an example depicting the usage of rsync for copying files without overwriting:
```
rsync -av —ignore-existing /home/user/folder1/ /home/user/folder2/
```
This command copies all files from `folder1` to `folder2` without overwriting any existing files in `folder2`. It lists the files being copied in the terminal due to the `-v` (verbose) option.
For instance, you have a text file `test1.txt` in `folder1` and `folder2` both. When you run the above command, it will not overwrite the `test1.txt` in `folder2` with the `test1.txt` from `folder1`.
But remember, the `—ignore-existing` flag will only prevent files with the same name being replaced. If there are new files on the source directory which are not in the destination directory, those will be copied.
This response extracts information from reliable and recognized sources like the man page of RSYNC (https://man7.org/linux/man-pages/man1/rsync.1.html), which is the official manual provided by the developer(s) of this tool.
To further understand the use of RSYNC and other available options, you might refer to the above-mentioned man page or other well-recognized resources like GeeksforGeeks (https://www.geeksforgeeks.org/rsync-command-in-linux-with-examples/), TecMint (https://www.tecmint.com/rsync-local-remote-file-synchronization-commands/), etc.
Therefore, using the `—ignore-existing` flag with the rsync command allows you to copy the files without overwriting existing files in the destination, thereby ensuring the preservation of your data.
