HardenedBSD/crypto/openssh/sftp.1

.\" $OpenBSD: sftp.1,v 1.143 2022/12/16 03:40:03 djm Exp $
.\"
.\" Copyright (c) 2001 Damien Miller.  All rights reserved.
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.Dd $Mdocdate: December 16 2022 $
.Dt SFTP 1
.Os
.Sh NAME
.Nm sftp
.Nd OpenSSH secure file transfer
.Sh SYNOPSIS
.Nm sftp
.Op Fl 46AaCfNpqrv
.Op Fl B Ar buffer_size
.Op Fl b Ar batchfile
.Op Fl c Ar cipher
.Op Fl D Ar sftp_server_command
.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 R Ar num_requests
.Op Fl S Ar program
.Op Fl s Ar subsystem | sftp_server
.Op Fl X Ar sftp_option
.Ar destination
.Sh DESCRIPTION
.Nm
is a file transfer program, similar to
.Xr ftp 1 ,
which performs all operations over an encrypted
.Xr ssh 1
transport.
It may also use many features of ssh, such as public key authentication and
compression.
.Pp
The
.Ar destination
may be specified either as
.Sm off
.Oo user @ Oc host Op : path
.Sm on
or as a URI in the form
.Sm off
.No sftp:// Oo user @ Oc host Oo : port Oc Op / path .
.Sm on
.Pp
If the
.Ar destination
includes a
.Ar path
and it is not a directory,
.Nm
will retrieve files automatically if a non-interactive
authentication method is used; otherwise it will do so after
successful interactive authentication.
.Pp
If no
.Ar path
is specified, or if the
.Ar path
is a directory,
.Nm
will log in to the specified
.Ar host
and enter interactive command mode, changing to the remote directory
if one was specified.
An optional trailing slash can be used to force the
.Ar path
to be interpreted as a directory.
.Pp
Since the destination formats use colon characters to delimit host
names from path names or port numbers, IPv6 addresses must be
enclosed in square brackets to avoid ambiguity.
.Pp
The options are as follows:
.Bl -tag -width Ds
.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 a
Attempt to continue interrupted transfers rather than overwriting
existing partial or complete copies of files.
If the partial contents differ from those being transferred,
then the resultant file is likely to be corrupt.
.It Fl B Ar buffer_size
Specify the size of the buffer that
.Nm
uses when transferring files.
Larger buffers require fewer round trips at the cost of higher
memory consumption.
The default is 32768 bytes.
.It Fl b Ar batchfile
Batch mode reads a series of commands from an input
.Ar batchfile
instead of
.Em stdin .
Since it lacks user interaction, it should be used in conjunction with
non-interactive authentication to obviate the need to enter a password
at connection time (see
.Xr sshd 8
and
.Xr ssh-keygen 1
for details).
.Pp
A
.Ar batchfile
of
.Sq \-
may be used to indicate standard input.
.Nm
will abort if any of the following
commands fail:
.Ic get , put , reget , reput , rename , ln ,
.Ic rm , mkdir , chdir , ls ,
.Ic lchdir , copy , cp , chmod , chown ,
.Ic chgrp , lpwd , df , symlink ,
and
.Ic lmkdir .
.Pp
Termination on error can be suppressed on a command by command basis by
prefixing the command with a
.Sq \-
character (for example,
.Ic -rm /tmp/blah* ) .
Echo of the command may be suppressed by prefixing the command with a
.Sq @
character.
These two prefixes may be combined in any order, for example
.Ic -@ls /bsd .
.It Fl C
Enables compression (via ssh's
.Fl C
flag).
.It Fl c Ar cipher
Selects the cipher to use for encrypting the data transfers.
This option is directly passed to
.Xr ssh 1 .
.It Fl D Ar sftp_server_command
Connect directly to a local sftp server
(rather than via
.Xr ssh 1 ) .
A command and arguments may be specified, for example
.Qq /path/sftp-server -el debug3 .
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
.Xr ssh 1 .
This option is directly passed to
.Xr ssh 1 .
.It Fl f
Requests that files be flushed to disk immediately after transfer.
When uploading files, this feature is only enabled if the server
implements the "fsync@openssh.com" extension.
.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 N
Disables quiet mode, e.g. to override the implicit quiet mode set by the
.Fl b
flag.
.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 sftp
command-line flag.
For example, to specify an alternate port use:
.Ic sftp -oPort=24 .
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 AddressFamily
.It BatchMode
.It BindAddress
.It BindInterface
.It CanonicalDomains
.It CanonicalizeFallbackLocal
.It CanonicalizeHostname
.It CanonicalizeMaxDots
.It CanonicalizePermittedCNAMEs
.It CASignatureAlgorithms
.It CertificateFile
.It CheckHostIP
.It Ciphers
.It Compression
.It ConnectionAttempts
.It ConnectTimeout
.It ControlMaster
.It ControlPath
.It ControlPersist
.It GlobalKnownHostsFile
.It GSSAPIAuthentication
.It GSSAPIDelegateCredentials
.It HashKnownHosts
.It Host
.It HostbasedAcceptedAlgorithms
.It HostbasedAuthentication
.It HostKeyAlgorithms
.It HostKeyAlias
.It Hostname
.It IdentitiesOnly
.It IdentityAgent
.It IdentityFile
.It IPQoS
.It KbdInteractiveAuthentication
.It KbdInteractiveDevices
.It KexAlgorithms
.It KnownHostsCommand
.It LogLevel
.It MACs
.It NoHostAuthenticationForLocalhost
.It NumberOfPasswordPrompts
.It PasswordAuthentication
.It PKCS11Provider
.It Port
.It PreferredAuthentications
.It ProxyCommand
.It ProxyJump
.It PubkeyAcceptedAlgorithms
.It PubkeyAuthentication
.It RekeyLimit
.It RequiredRSASize
.It SendEnv
.It ServerAliveInterval
.It ServerAliveCountMax
.It SetEnv
.It StrictHostKeyChecking
.It TCPKeepAlive
.It UpdateHostKeys
.It User
.It UserKnownHostsFile
.It VerifyHostKeyDNS
.El
.It Fl P Ar port
Specifies the port to connect to on the remote host.
.It Fl p
Preserves modification times, access times, and modes from the
original files transferred.
.It Fl q
Quiet mode: disables the progress meter as well as warning and
diagnostic messages from
.Xr ssh 1 .
.It Fl R Ar num_requests
Specify how many requests may be outstanding at any one time.
Increasing this may slightly improve file transfer speed
but will increase memory usage.
The default is 64 outstanding requests.
.It Fl r
Recursively copy entire directories when uploading and downloading.
Note that
.Nm
does not follow symbolic links encountered in the tree traversal.
.It Fl S Ar program
Name of the
.Ar program
to use for the encrypted connection.
The program must understand
.Xr ssh 1
options.
.It Fl s Ar subsystem | sftp_server
Specifies the SSH2 subsystem or the path for an sftp server
on the remote host.
A path is useful when the remote
.Xr sshd 8
does not have an sftp subsystem configured.
.It Fl v
Raise logging level.
This option is also passed to ssh.
.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
.Sh INTERACTIVE COMMANDS
Once in interactive mode,
.Nm
understands a set of commands similar to those of
.Xr ftp 1 .
Commands are case insensitive.
Pathnames that contain spaces must be enclosed in quotes.
Any special characters contained within pathnames that are recognized by
.Xr glob 3
must be escaped with backslashes
.Pq Sq \e .
.Bl -tag -width Ds
.It Ic bye
Quit
.Nm sftp .
.It Ic cd Op Ar path
Change remote directory to
.Ar path .
If
.Ar path
is not specified, then change directory to the one the session started in.
.It Xo Ic chgrp
.Op Fl h
.Ar grp
.Ar path
.Xc
Change group of file
.Ar path
to
.Ar grp .
.Ar path
may contain
.Xr glob 7
characters and may match multiple files.
.Ar grp
must be a numeric GID.
.Pp
If the
.Fl h
flag is specified, then symlinks will not be followed.
Note that this is only supported by servers that implement
the "lsetstat@openssh.com" extension.
.It Xo Ic chmod
.Op Fl h
.Ar mode
.Ar path
.Xc
Change permissions of file
.Ar path
to
.Ar mode .
.Ar path
may contain
.Xr glob 7
characters and may match multiple files.
.Pp
If the
.Fl h
flag is specified, then symlinks will not be followed.
Note that this is only supported by servers that implement
the "lsetstat@openssh.com" extension.
.It Xo Ic chown
.Op Fl h
.Ar own
.Ar path
.Xc
Change owner of file
.Ar path
to
.Ar own .
.Ar path
may contain
.Xr glob 7
characters and may match multiple files.
.Ar own
must be a numeric UID.
.Pp
If the
.Fl h
flag is specified, then symlinks will not be followed.
Note that this is only supported by servers that implement
the "lsetstat@openssh.com" extension.
.It Ic copy Ar oldpath Ar newpath
Copy remote file from
.Ar oldpath
to
.Ar newpath .
.Pp
Note that this is only supported by servers that implement the "copy-data"
extension.
.It Ic cp Ar oldpath Ar newpath
Alias to
.Ic copy
command.
.It Xo Ic df
.Op Fl hi
.Op Ar path
.Xc
Display usage information for the filesystem holding the current directory
(or
.Ar path
if specified).
If the
.Fl h
flag is specified, the capacity information will be displayed using
"human-readable" suffixes.
The
.Fl i
flag requests display of inode information in addition to capacity information.
This command is only supported on servers that implement the
.Dq statvfs@openssh.com
extension.
.It Ic exit
Quit
.Nm sftp .
.It Xo Ic get
.Op Fl afpR
.Ar remote-path
.Op Ar local-path
.Xc
Retrieve the
.Ar remote-path
and store it on the local machine.
If the local
path name is not specified, it is given the same name it has on the
remote machine.
.Ar remote-path
may contain
.Xr glob 7
characters and may match multiple files.
If it does and
.Ar local-path
is specified, then
.Ar local-path
must specify a directory.
.Pp
If the
.Fl a
flag is specified, then attempt to resume partial transfers of existing files.
Note that resumption assumes that any partial copy of the local file matches
the remote copy.
If the remote file contents differ from the partial local copy then the
resultant file is likely to be corrupt.
.Pp
If the
.Fl f
flag is specified, then
.Xr fsync 2
will be called after the file transfer has completed to flush the file
to disk.
.Pp
If the
.Fl p
.\" undocumented redundant alias
.\" or
.\" .Fl P
flag is specified, then full file permissions and access times are
copied too.
.Pp
If the
.Fl R
.\" undocumented redundant alias
.\" or
.\" .Fl r
flag is specified then directories will be copied recursively.
Note that
.Nm
does not follow symbolic links when performing recursive transfers.
.It Ic help
Display help text.
.It Ic lcd Op Ar path
Change local directory to
.Ar path .
If
.Ar path
is not specified, then change directory to the local user's home directory.
.It Ic lls Op Ar ls-options Op Ar path
Display local directory listing of either
.Ar path
or current directory if
.Ar path
is not specified.
.Ar ls-options
may contain any flags supported by the local system's
.Xr ls 1
command.
.Ar path
may contain
.Xr glob 7
characters and may match multiple files.
.It Ic lmkdir Ar path
Create local directory specified by
.Ar path .
.It Xo Ic ln
.Op Fl s
.Ar oldpath
.Ar newpath
.Xc
Create a link from
.Ar oldpath
to
.Ar newpath .
If the
.Fl s
flag is specified the created link is a symbolic link, otherwise it is
a hard link.
.It Ic lpwd
Print local working directory.
.It Xo Ic ls
.Op Fl 1afhlnrSt
.Op Ar path
.Xc
Display a remote directory listing of either
.Ar path
or the current directory if
.Ar path
is not specified.
.Ar path
may contain
.Xr glob 7
characters and may match multiple files.
.Pp
The following flags are recognized and alter the behaviour of
.Ic ls
accordingly:
.Bl -tag -width Ds
.It Fl 1
Produce single columnar output.
.It Fl a
List files beginning with a dot
.Pq Sq \&. .
.It Fl f
Do not sort the listing.
The default sort order is lexicographical.
.It Fl h
When used with a long format option, use unit suffixes: Byte, Kilobyte,
Megabyte, Gigabyte, Terabyte, Petabyte, and Exabyte in order to reduce
the number of digits to four or fewer using powers of 2 for sizes (K=1024,
M=1048576, etc.).
.It Fl l
Display additional details including permissions
and ownership information.
.It Fl n
Produce a long listing with user and group information presented
numerically.
.It Fl r
Reverse the sort order of the listing.
.It Fl S
Sort the listing by file size.
.It Fl t
Sort the listing by last modification time.
.El
.It Ic lumask Ar umask
Set local umask to
.Ar umask .
.It Ic mkdir Ar path
Create remote directory specified by
.Ar path .
.It Ic progress
Toggle display of progress meter.
.It Xo Ic put
.Op Fl afpR
.Ar local-path
.Op Ar remote-path
.Xc
Upload
.Ar local-path
and store it on the remote machine.
If the remote path name is not specified, it is given the same name it has
on the local machine.
.Ar local-path
may contain
.Xr glob 7
characters and may match multiple files.
If it does and
.Ar remote-path
is specified, then
.Ar remote-path
must specify a directory.
.Pp
If the
.Fl a
flag is specified, then attempt to resume partial
transfers of existing files.
Note that resumption assumes that any partial copy of the remote file
matches the local copy.
If the local file contents differ from the remote local copy then
the resultant file is likely to be corrupt.
.Pp
If the
.Fl f
flag is specified, then a request will be sent to the server to call
.Xr fsync 2
after the file has been transferred.
Note that this is only supported by servers that implement
the "fsync@openssh.com" extension.
.Pp
If the
.Fl p
.\" undocumented redundant alias
.\" or
.\" .Fl P
flag is specified, then full file permissions and access times are
copied too.
.Pp
If the
.Fl R
.\" undocumented redundant alias
.\" or
.\" .Fl r
flag is specified then directories will be copied recursively.
Note that
.Nm
does not follow symbolic links when performing recursive transfers.
.It Ic pwd
Display remote working directory.
.It Ic quit
Quit
.Nm sftp .
.It Xo Ic reget
.Op Fl fpR
.Ar remote-path
.Op Ar local-path
.Xc
Resume download of
.Ar remote-path .
Equivalent to
.Ic get
with the
.Fl a
flag set.
.It Xo Ic reput
.Op Fl fpR
.Ar local-path
.Op Ar remote-path
.Xc
Resume upload of
.Ar local-path .
Equivalent to
.Ic put
with the
.Fl a
flag set.
.It Ic rename Ar oldpath newpath
Rename remote file from
.Ar oldpath
to
.Ar newpath .
.It Ic rm Ar path
Delete remote file specified by
.Ar path .
.It Ic rmdir Ar path
Remove remote directory specified by
.Ar path .
.It Ic symlink Ar oldpath newpath
Create a symbolic link from
.Ar oldpath
to
.Ar newpath .
.It Ic version
Display the
.Nm
protocol version.
.It Ic \&! Ns Ar command
Execute
.Ar command
in local shell.
.It Ic \&!
Escape to local shell.
.It Ic \&?
Synonym for help.
.El
.Sh SEE ALSO
.Xr ftp 1 ,
.Xr ls 1 ,
.Xr scp 1 ,
.Xr ssh 1 ,
.Xr ssh-add 1 ,
.Xr ssh-keygen 1 ,
.Xr ssh_config 5 ,
.Xr glob 7 ,
.Xr sftp-server 8 ,
.Xr sshd 8
.Rs
.%A T. Ylonen
.%A S. Lehtinen
.%T "SSH File Transfer Protocol"
.%N draft-ietf-secsh-filexfer-00.txt
.%D January 2001
.%O work in progress material
.Re