在linux安装部署或者升级分布式系统时，经常要重当前主机拷贝文件到集群中其他的主机节点，或者从其他主机节点拷贝文件到当前主机。
我们知道cp命令是同一主机下面文件的拷贝，而scp命令就是linux下实现远程主机之间文件拷贝的命令，支持向远程主机‘推文件’和向远程主机‘拉文件’的方式。
输入scp -h看看选项：
$ scp -h
unknown option -- h
usage: scp [-12346BCpqrv] [-c cipher] [-F ssh_config] [-i identity_file]
[-l limit] [-o ssh_option] [-P port] [-S program]
[[user@]host1:]file1 ... [[user@]host2:]file2
输入man scp看看说明：
SCP(1) BSD General Commands Manual SCP(1)
NAME
scp — secure copy (remote file copy program)
SYNOPSIS
scp [-12346BCpqrv] [-c cipher] [-F ssh_config] [-i identity_file] [-l limit] [-o ssh_option] [-P port] [-S program] [[user@]host1:]file1 ... [[user@]host2:]file2
DESCRIPTION
scp copies files between hosts on a network. It uses ssh(1) for data transfer, and uses the same authentication and provides the same security as ssh(1). scp will ask for passwords or
passphrases if they are needed for authentication.
File names may contain a user and host specification to indicate that the file is to be copied to/from that host. Local file names can be made explicit using absolute or relative pathnames
to avoid scp treating file names containing ‘:’ as host specifiers. Copies between two remote hosts are also permitted.
The options are as follows:
-1 Forces scp to use protocol 1.
-2 Forces scp to use protocol 2.
-3 Copies between two remote hosts are transferred through the local host. Without this option the data is copied directly between the two remote hosts. Note that this option dis‐
ables the progress meter.
-4 Forces scp to use IPv4 addresses only.
-6 Forces scp to use IPv6 addresses only.
-B Selects batch mode (prevents asking for passwords or passphrases).
-C Compression enable. Passes the -C flag to ssh(1) to enable compression.
-c cipher
Selects the cipher to use for encrypting the data transfer. This option is directly passed to ssh(1).
-F ssh_config
Specifies an alternative per-user configuration file for ssh. This option is directly passed to ssh(1).
-i identity_file
Selects the file from which the identity (private key) for public key authentication is read. This option is directly passed to ssh(1).
-l limit
Limits the used bandwidth, specified in Kbit/s.
-o ssh_option
Can be used to pass options to ssh in the format used in ssh_config(5). This is useful for specifying options for which there is no separate scp command-line flag. For full
details of the options listed below, and their possible values, see ssh_config(5).
AddressFamily
BatchMode
BindAddress
CanonicalDomains
CanonicalizeFallbackLocal
CanonicalizeHostname
CanonicalizeMaxDots
CanonicalizePermittedCNAMEs
CertificateFile
ChallengeResponseAuthentication
CheckHostIP
Cipher
Ciphers
Compression
CompressionLevel
ConnectionAttempts
ConnectTimeout
ControlMaster
ControlPath
ControlPersist
GlobalKnownHostsFile
GSSAPIAuthentication
GSSAPIDelegateCredentials
HashKnownHosts
Host
HostbasedAuthentication
HostbasedKeyTypes
HostKeyAlgorithms
HostKeyAlias
HostName
IdentityFile
IdentitiesOnly
IPQoS
KbdInteractiveAuthentication
KbdInteractiveDevices
KexAlgorithms
LogLevel
MACs
NoHostAuthenticationForLocalhost
NumberOfPasswordPrompts
PasswordAuthentication
PKCS11Provider
Port
PreferredAuthentications
Protocol
ProxyCommand
PubkeyAcceptedKeyTypes
PubkeyAuthentication
RekeyLimit
RhostsRSAAuthentication
RSAAuthentication
SendEnv
ServerAliveInterval
ServerAliveCountMax
StrictHostKeyChecking
TCPKeepAlive
UpdateHostKeys
UsePrivilegedPort
User
UserKnownHostsFile
VerifyHostKeyDNS
-P port
Specifies the port to connect to on the remote host. Note that this option is written with a capital ‘P’, because -p is already reserved for preserving the times and modes of the
file.
-p Preserves modification times, access times, and modes from the original file.
-q Quiet mode: disables the progress meter as well as warning and diagnostic messages from ssh(1).
-r Recursively copy entire directories. Note that scp follows symbolic links encountered in the tree traversal.
-S program
Name of program to use for the encrypted connection. The program must understand ssh(1) options.
-v Verbose mode. Causes scp and ssh(1) to print debugging messages about their progress. This is helpful in debugging connection, authentication, and configuration problems.
EXIT STATUS
The scp utility exits 0 on success, and >0 if an error occurs.
SEE ALSO
sftp(1), ssh(1), ssh-add(1), ssh-agent(1), ssh-keygen(1), ssh_config(5), sshd(8)
HISTORY
scp is based on the rcp program in BSD source code from the Regents of the University of California.
AUTHORS
Timo Rinne
Tatu Ylonen
BSD September 25, 2015 BSD
里面常用的选项有，-r 拷贝目录，-v 显示拷贝时的调试信息，对于拷贝文件出错有帮助，-l 限制拷贝时带宽等。
