cpgr

While cpgr is not a direct command, its implied usage follows the syntax of cp with the specified options:

cp -gr [OPTION]... SOURCE... DIRECTORY
cp -gr [OPTION]... SOURCE DESTINATION

Examples:
cp -gr /path/to/source_directory /path/to/destination_directory
cp -gr file1.txt file2.txt /path/to/target_directory (Copies files and preserves group if source is a file)

SOURCE
    The path to the file(s) or directory(ies) to be copied. Multiple sources can be specified if the destination is a directory.

DESTINATION
    The target path where the source(s) will be copied. Can be a new file name (for a single source) or an existing directory (for single or multiple sources).

-g, --preserve=group
    Preserves the group ownership of the source files/directories in the destination. This operation typically requires root privileges or the invoking user to be a member of the target group.

-r, -R, --recursive
    Copies directories and their contents (subdirectories and files) recursively. This option is essential for copying entire folder structures.

-a, --archive
    Copies in archive mode, preserving as much as possible of the original file's attributes: permissions, timestamps, context, links (does not follow symlinks), etc. This option implies -dR --preserve=all, and often encompasses the functionality of -g and -r.

-p, --preserve=mode,ownership,timestamps
    Preserves the mode (permissions), ownership (user and group), and timestamps of the source file/directory in the copy.

-v, --verbose
    Explains what is being done by printing the name of each file or directory as it is copied.

--target-directory=DIRECTORY
    Specifies the destination DIRECTORY explicitly. This is useful when sources could be confused with a destination, for instance when copying a single source named 'target_dir'.

The command cpgr is not a standard Linux command. It is highly probable that it is a shorthand or a common typo for the cp command used with the -g and -r (or -R) options. The cp (copy) command is a fundamental utility in Unix-like operating systems used for copying files and directories.

When invoked as cp -gr, it performs two main functions:

1. Recursive Copy (-r or -R): This option allows cp to copy directories and their entire contents (subdirectories, files, etc.). Without this option, cp can only copy individual files or an empty directory, and will error out if you try to copy a directory.

2. Preserve Group Ownership (-g): This option instructs cp to preserve the group ownership of the source files/directories in the copied destination. By default, new files and directories created by cp typically inherit the group of the user executing the command, or the default group of the parent directory. The -g option ensures that the original group associated with the source file/directory is maintained in the copy, provided the user has the necessary permissions (typically root privileges or membership in the target group).

Using cp -gr, especially with the -g option, requires careful consideration:

1. Permissions: Preserving group ownership (-g) often requires the user executing the command to have root privileges or to be a member of the target group on the destination file system. If not, the group ownership will default to the effective group ID of the user or the default group of the parent directory.

2. Disk Space: Copying large directories recursively can consume significant disk space on the destination.

3. Symbolic Links: By default, cp -r copies the contents of symbolic links to directories (i.e., it dereferences them). To copy the symbolic link itself, use the -P or --no-dereference option. The -a (archive) option implies -P.

4. Atomic Operations: cp is not atomic; if interrupted, it may leave partial or corrupted copies. For critical or large transfers, rsync is often a more robust choice.

For the cp command, the -r and -R options are typically synonymous and both denote recursive copying of directories. There is generally no functional difference between them for cp on modern Linux systems. Historically, -R was sometimes used to indicate a preference for copying symbolic links as-is (not dereferencing them), but this behavior is now primarily controlled by the -P or --no-dereference options, or implied by -a (archive mode).

When copying files and directories with cp without specific preservation options, the new copies will usually have the ownership (user and group) of the user executing the command and default permissions based on the user's umask. The -g option specifically preserves the group ownership. To preserve user ownership as well, the -p option (which preserves mode, ownership, and timestamps) or the more comprehensive -a (archive) option should be used. Preserving ownership typically requires root privileges, as ordinary users cannot arbitrarily set the ownership of files to another user.

The cp command is one of the oldest and most fundamental utilities in the Unix operating system, dating back to its earliest versions in the 1970s. Its core functionality for copying files has remained largely consistent throughout its history. Options like -g (group preservation) and -r (recursive) were added as the system evolved to handle more complex file system operations and directory structures. Its inclusion in POSIX standards ensures its ubiquitous presence and consistent behavior across various Unix-like systems, including Linux.

cp(1): The core copy command., mv(1): Move or rename files and directories., rm(1): Remove files or directories., ln(1): Make links between files., rsync(1): A more powerful and flexible tool for copying and synchronizing files, especially across networks, with options for preserving attributes, incremental updates, and resuming transfers.