.\"
.\" scp.1
.\"
.\" Author: Tatu Ylonen <ylo@cs.hut.fi>
.\"
.\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
.\"                    All rights reserved
.\"
.\" Created: Sun May  7 00:14:37 1995 ylo
.\"
.\" $OpenBSD: scp.1,v 1.115 2025/10/04 21:41:35 naddy Exp $
.\"
.Dd $Mdocdate: October 4 2025 $
.Dt SCP 1
.Os
.Sh NAME
.Nm scp
.Nd OpenSSH secure file copy
.Sh SYNOPSIS
.Nm scp
.Op Fl 346ABCOpqRrsTv
.Op Fl c Ar cipher
.Op Fl D Ar sftp_server_path
.Op Fl F Ar ssh_config
.Op Fl i Ar identity_file
.Op Fl J Ar destination
.Op Fl l Ar limit
.Op Fl o Ar ssh_option
.Op Fl P Ar port
.Op Fl S Ar program
.Op Fl X Ar sftp_option
.Ar source ... target
.Sh DESCRIPTION
.Nm
copies files between hosts on a network.
.Pp
.Nm
uses the SFTP protocol over an
.Xr ssh 1
connection for data transfer, and uses the same authentication and provides
the same security as a login session.
.Pp
.Nm
will ask for passwords or passphrases if they are needed for
authentication.
.Pp
The
.Ar source
and
.Ar target
may be specified as a local pathname, a remote host with optional path
in the form
.Sm off
.Oo user @ Oc host : Op path ,
.Sm on
or a URI in the form
.Sm off
.No scp:// Oo user @ Oc host Oo : port Oc Op / path .
.Sm on
Local file names can be made explicit using absolute or relative pathnames
to avoid
.Nm
treating file names containing
.Sq :\&
as host specifiers.
.Pp
When copying between two remote hosts, if the URI format is used, a
.Ar port
cannot be specified on the
.Ar target
if the
.Fl R
option is used.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl 3
Copies between two remote hosts are transferred through the local host.
This mode is the default,
but see also the
.Fl R
option for copying data directly between two remote hosts.
Note that when using the legacy SCP protocol (via the
.Fl O
flag), this option
selects batch mode for the second host as
.Nm
cannot ask for passwords or passphrases for both hosts.
.It Fl 4
Forces
.Nm
to use IPv4 addresses only.
.It Fl 6
Forces
.Nm
to use IPv6 addresses only.
.It Fl A
Allows forwarding of
.Xr ssh-agent 1
to the remote system.
The default is not to forward an authentication agent.
.It Fl B
Selects batch mode (prevents asking for passwords or passphrases).
.It Fl C
Compression enable.
Passes the
.Fl C
flag to
.Xr ssh 1
to enable compression.
.It Fl c Ar cipher
Selects the cipher to use for encrypting the data transfer.
This option is directly passed to
.Xr ssh 1 .
.It Fl D Ar sftp_server_path
Connect directly to a local SFTP server program rather than a
remote one via
.Xr ssh 1 .
This option may be useful in debugging the client and server.
.It Fl F Ar ssh_config
Specifies an alternative
per-user configuration file for
.Nm ssh .
This option is directly passed to
.Xr ssh 1 .
.It Fl i Ar identity_file
Selects the file from which the identity (private key) for public key
authentication is read.
This option is directly passed to
.Xr ssh 1 .
.It Fl J Ar destination
Connect to the target host by first making an
.Nm
connection to the jump host described by
.Ar destination
and then establishing a TCP forwarding to the ultimate destination from
there.
Multiple jump hops may be specified separated by comma characters.
This is a shortcut to specify a
.Cm ProxyJump
configuration directive.
This option is directly passed to
.Xr ssh 1 .
.It Fl l Ar limit
Limits the used bandwidth, specified in Kbit/s.
.It Fl O
Use the legacy SCP protocol for file transfers instead of the SFTP protocol.
Forcing the use of the SCP protocol may be necessary for servers that do
not implement SFTP, for backwards-compatibility for particular filename
wildcard patterns and for expanding paths with a
.Sq ~
prefix for older SFTP servers.
.It Fl o Ar ssh_option
Can be used to pass options to
.Nm ssh
in the format used in
.Xr ssh_config 5 .
This is useful for specifying options
for which there is no separate
.Nm scp
command-line flag.
For full details of the options listed below, and their possible values, see
.Xr ssh_config 5 .
.Pp
.Bl -tag -width Ds -offset indent -compact
.It AddKeysToAgent
.It AddressFamily
.It BatchMode
.It BindAddress
.It BindInterface
.It CASignatureAlgorithms
.It CanonicalDomains
.It CanonicalizeFallbackLocal
.It CanonicalizeHostname
.It CanonicalizeMaxDots
.It CanonicalizePermittedCNAMEs
.It CertificateFile
.It ChannelTimeout
.It CheckHostIP
.It Ciphers
.It ClearAllForwardings
.It Compression
.It ConnectTimeout
.It ConnectionAttempts
.It ControlMaster
.It ControlPath
.It ControlPersist
.It DynamicForward
.It EnableEscapeCommandline
.It EnableSSHKeysign
.It EscapeChar
.It ExitOnForwardFailure
.It FingerprintHash
.It ForkAfterAuthentication
.It ForwardAgent
.It ForwardX11
.It ForwardX11Timeout
.It ForwardX11Trusted
.It GSSAPIAuthentication
.It GSSAPIDelegateCredentials
.It GatewayPorts
.It GlobalKnownHostsFile
.It HashKnownHosts
.It Host
.It HostKeyAlgorithms
.It HostKeyAlias
.It HostbasedAcceptedAlgorithms
.It HostbasedAuthentication
.It Hostname
.It IPQoS
.It IdentitiesOnly
.It IdentityAgent
.It IdentityFile
.It IgnoreUnknown
.It Include
.It KbdInteractiveAuthentication
.It KbdInteractiveDevices
.It KexAlgorithms
.It KnownHostsCommand
.It LocalCommand
.It LocalForward
.It LogLevel
.It LogVerbose
.It MACs
.It NoHostAuthenticationForLocalhost
.It NumberOfPasswordPrompts
.It ObscureKeystrokeTiming
.It PKCS11Provider
.It PasswordAuthentication
.It PermitLocalCommand
.It PermitRemoteOpen
.It Port
.It PreferredAuthentications
.It ProxyCommand
.It ProxyJump
.It ProxyUseFdpass
.It PubkeyAcceptedAlgorithms
.It PubkeyAuthentication
.It RekeyLimit
.It RemoteCommand
.It RemoteForward
.It RequestTTY
.It RequiredRSASize
.It RevokedHostKeys
.It SecurityKeyProvider
.It SendEnv
.It ServerAliveCountMax
.It ServerAliveInterval
.It SessionType
.It SetEnv
.It StdinNull
.It StreamLocalBindMask
.It StreamLocalBindUnlink
.It StrictHostKeyChecking
.It SyslogFacility
.It TCPKeepAlive
.It Tag
.It Tunnel
.It TunnelDevice
.It UpdateHostKeys
.It User
.It UserKnownHostsFile
.It VerifyHostKeyDNS
.It VisualHostKey
.It XAuthLocation
.El
.It Fl P Ar port
Specifies the port to connect to on the remote host.
Note that this option is written with a capital
.Sq P ,
because
.Fl p
is already reserved for preserving the times and mode bits of the file.
.It Fl p
Preserves modification times, access times, and file mode bits from the
source file.
.It Fl q
Quiet mode: disables the progress meter as well as warning and diagnostic
messages from
.Xr ssh 1 .
.It Fl R
Copies between two remote hosts are transferred through the local host
by default.
This option instead copies between two remote hosts by connecting to the origin
host and executing
.Nm
there.
This requires that
.Nm
running on the origin host can authenticate to the destination host without
requiring a password.
.It Fl r
Recursively copy entire directories.
Note that
.Nm
follows symbolic links encountered in the tree traversal.
.It Fl S Ar program
Name of
.Ar program
to use for the encrypted connection.
The program must understand
.Xr ssh 1
options.
.It Fl T
Disable strict filename checking.
By default when copying files from a remote host to a local directory
.Nm
checks that the received filenames match those requested on the command-line
to prevent the remote end from sending unexpected or unwanted files.
Because of differences in how various operating systems and shells interpret
filename wildcards, these checks may cause wanted files to be rejected.
This option disables these checks at the expense of fully trusting that
the server will not send unexpected filenames.
.It Fl v
Verbose mode.
Causes
.Nm
and
.Xr ssh 1
to print debugging messages about their progress.
This is helpful in
debugging connection, authentication, and configuration problems.
.It Fl X Ar sftp_option
Specify an option that controls aspects of SFTP protocol behaviour.
The valid options are:
.Bl -tag -width Ds
.It Cm nrequests Ns = Ns Ar value
Controls how many concurrent SFTP read or write requests may be in progress
at any point in time during a download or upload.
By default 64 requests may be active concurrently.
.It Cm buffer Ns = Ns Ar value
Controls the maximum buffer size for a single SFTP read/write operation used
during download or upload.
By default a 32KB buffer is used.
.El
.El
.Pp
Usage of SCP protocol can be blocked by creating a world-readable
.Ar /etc/ssh/disable_scp
file. If this file exists, when SCP protocol is in use (either remotely or 
via the
.Fl O
option), the program will exit.
.Sh EXIT STATUS
.Ex -std scp
.Sh SEE ALSO
.Xr sftp 1 ,
.Xr ssh 1 ,
.Xr ssh-add 1 ,
.Xr ssh-agent 1 ,
.Xr ssh-keygen 1 ,
.Xr ssh_config 5 ,
.Xr sftp-server 8 ,
.Xr sshd 8
.Sh HISTORY
.Nm
is based on the rcp program in
.Bx
source code from the Regents of the University of California.
.Pp
Since OpenSSH 9.0,
.Nm
has used the SFTP protocol for transfers by default.
.Sh AUTHORS
.An Timo Rinne Aq Mt tri@iki.fi
.An Tatu Ylonen Aq Mt ylo@cs.hut.fi
.Sh CAVEATS
The legacy SCP protocol (selected by the
.Fl O
flag) requires execution of the remote user's shell to perform
.Xr glob 3
pattern matching.
This requires careful quoting of any characters that have special meaning to
the remote shell, such as quote characters.
