rcp Command

Commands Reference, Volume 4

rcp Command

Purpose

Transfers files between a local and a remote host or between two remote hosts.

Syntax

rcp [-p] [-F] [-k realm ] { {User@Host:File | Host:File | File } { User@Host:File | Host:File | File | User@Host:Directory | Host:Directory | Directory } | [-r] { User@Host:Directory | Host:Directory |Directory } { User@Host:Directory | Host:Directory | Directory } }

Description

The /usr/bin/rcp command is used to copy one or more files between the local host and a remote host, between two remote hosts, or between files at the same remote host.

Remote destination files and directories require a specified Host: parameter. If a remote host name is not specified for either the source or the destination, the rcp command is equivalent to the cp command. Local file and directory names do not require a Host: parameter.

Note: The rcp command assumes that a : (colon) terminates a host name,. When you want to use a : in a filename, use a / (slash) in front of the filename or use the full path name, including the /.

If a Host is not prefixed by a User@ parameter, the local user name is used at the remote host. If a User@ parameter is entered, that name is used.

If the path for a file or directory on a remote host is not specified or is not fully qualified, the path is interpreted as beginning at the home directory for the remote user account. Additionally, any metacharacters that must be interpreted at a remote host must be quoted using a \ (backslash), a " (double quotation mark), or a ' (single quotation mark).

File Permissions and Ownership

By default, the permissions mode and ownership of an existing destination file are preserved. Normally, if a destination file does not exist, the permissions mode of the destination file is equal to the permissions mode of the source file as modified by the umask command (a special command in the Korn shell) at the destination host. If the rcp command -p flag is set, the modification time and mode of source files are preserved at the destination host.

The user name entered for the remote host determines the file access privileges the rcp command uses at that host. Additionally, the user name given to a destination host determines the ownership and access modes of the resulting destination file or files.

Using Standard AIX Authentication

The remote host allows access if one of the following conditions is satisfied:

The local host is included in the remote host /etc/hosts.equiv file and the remote user is not the root user.
The local host and user name is included in a $HOME/.rhosts file on the remote user account.

Although you can set any permissions for the $HOME/.rhosts file, it is recommended that the permissions of the .rhosts file be set to 600 (read and write by owner only).

In addition to the preceding conditions, the rcp command also allows access to the remote host if the remote user account does not have a password defined. However, for security reasons, the use of a password on all user accounts is recommended.

For Kerberos 5 Authentication

The remote host allows access only if all of the following conditions are satisfied:

The local user has current DCE credentials.

The local and remote systems are configured for Kerberos 5 authentication (On non-AIX remote systems, this may not be necessary. It is necessary that a daemon is listening to the klogin port).

The remote system accepts the DCE credentials as sufficient for access to the remote account. See the kvalid_user function for additional information.

rcp and Named Pipelines

Do not use the rcp command to copy named pipelines, or FIFOs, (special files created with the mknod -p command).The rcp command uses the open subroutine on the files that it copies, and this subroutine blocks on blocking devices like a FIFO pipe.

Flags

-p

Preserves the modification times and modes of the source files in the copies sent to the destination only if the user has root authority or is the owner of the destination. Without this flag, the umask command at the destination modifies the mode of the destination file, and the modification time of the destination file is set to the time the file is received.

When this flag is not used, the umask being honored is the value stored in the appropriate database. It is not the value that is set by issuing the umask command. The permission and ownership values that result from the umask command do not affect those stored in the database.

-r

Recursively copies, for directories only, each file and subdirectory in the source directory into the destination directory.

-F Causes the credentials to be forwarded. In addition, the credentials on the remote system will be marked forwardable (allowing them to be passed to another remote system). This flag will be ignored if Kerberos 5 is not the current authentication method. Authentication will fail if the current DCE credentials are not marked forwardable. -k realm Allows the user to specify the realm of the remote station if it is different from the local systems realm. For these purposes, a realm is synonymous with a DCE cell. This flag will be ignored if Kerberos 5 is not the current authentication method.

Parameters

Host:File	Specifies the host name (Host) and file name (File) of the remote destination file, separated by a : (colon). Note: Because the rcp command assumes that a : (colon) terminates a host name, you must insert a \ (backslash) before any colons that are embedded in the local file and directory names.
User@Host:File	Specifies the user name (User@) that the rcp command uses to set ownership of the transferred file, the host name (Host), and file name (File) of the remote destination file. The user name entered for the remote host determines the file access privileges the rcp command uses at that host.
File	Specifies the file name of the local destination file.
Host:Directory	Specifies the host name (Host) and directory name (Directory) of the remote destination directory. Note: Because the rcp command assumes that a : (colon) terminates a host name, you must insert a \ (backslash) before any colons that are embedded in the local file and directory names.
User@Host:Directory	Specifies the user name (User@) the rcp command uses to set ownership of the transferred file, the host name (Host), and directory name (Directory) of the remote destination directory. The user name entered for the remote host determines the file access privileges the rcp command uses at that host.
Directory	The directory name of the local destination directory.

Examples

In the following examples, the local host is listed in the /etc/hosts.equiv file at the remote host.

To copy a local file to a remote host, enter:
```
rcp localfile host2:/home/eng/jane
```
The file localfile from the local host is copied to the remote host host2.
To copy a remote file from one remote host to another remote host, enter:
```
rcp host1:/home/eng/jane/newplan host2:/home/eng/mary
```
The file /home/eng/jane/newplan is copied from remote host host1 to remote host host2.
To send the directory subtree from the local host to a remote host and preserve the modification times and modes, enter:
```
rcp -p -r report jane@host2:report
```
The directory subtree report is copied from the local host to the home directory of user jane at remote host host2 and all modes and modification times are preserved. The remote file /home/jane/.rhosts includes an entry specifying the local host and user name.

Related Information

The cp command, ftp command, rlogin command, rsh command, telnet command, tftp command, umask command.

The rshd and krshd daemon.

The kvalid_user function.

The .rhosts file format, hosts.equiv file format.

Network Overview in AIX Version 4.3 System Management Guide: Communications and Networks.

Secure Rcmds in AIX Version 4.3 System User's Guide: Communications and Networks.