前言
有时候不可避免的需要将文件复制到另外一台服务器上，那么这时就可以使用scp命令远程拷贝文件，scp命令是基于SSH协议，在复制的过程中数据都是加密过的，会比明文传输更为安全。
一.命令介绍
依旧惯例，先到scp的帮助文档中查看命令的概述
NAME
scp — secure copy (remote file copy program)
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 per‐
mitted.
scp(secure copy)命令，主要功能是用来远程拷贝文件，可以在多台Linux系统之间复制文件或目录，有些类似于cp命令的功能，但复制的范围是网络上的另一台主机。
二. 命令语法
scp命令语法格式：scp 参数 文件
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
三. 常用参数
文档中一共有这么多的参数，总结一些比较常用的；
-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 disables 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
-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 disables 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).
常用参数：
| 命令选项 | 含义 |
|---|---|
| -1 | 使用ssh协议版本1 |
| -2 | 使用ssh协议版本2 |
| -4 | 使用ipv4 |
| 6 | 使用ipv6 |
| -B | 以批处理模式运行 |
| -C | 使用压缩 |
| -F | 指定ssh配置文件 |
| -l | 指定带宽限制 |
| -o | 指定使用的ssh选项 |
| -P | 指定远程主机的端口号 |
| -p | 保留文件的修改时间，访问时间和权限模式 |
| -q | 不显示复制进度 |
| -r | 以递归的方式进行复制 |
四. 参考实例
4.1 从本地远程复制到另一台服务器
4.1.1 拷贝文件到远程服务器
命令格式： 拷贝文件
第一种方式：指定用户名，将文件远程拷贝到另外一台服务器的目录下，命令执行后再输入密码。
scp local_file remote_username@remote_ip:remote_folder
第二种方式：指定用户名，将文件远程拷贝到另外一台服务器下，文件可以修改成其他名字，相当于远程拷贝重命名；命令执行后在输入密码。
scp local_file remote_username@remote_ip:remote_file
第三种方式：不指定用户名，将文件远程拷贝到另外一台服务器的目录下，命令执行后需要输入用户名和密码
scp local_file remote_ip:remote_folder
第四种方式：不指定用户名，将文件远程拷贝到另外一台服务器下，文件可以修改成其他名字，相当于远程拷贝重命名；命令执行后在输入密码。
scp local_file remote_ip:remote_file
案例演示：
scp /usr/local/nginx/conf/nginx.conf [email protected]:/usr/local/nginx/conf
scp /usr/local/nginx/conf/nginx.conf [email protected]:/usr/local/nginx/conf/nginx.conf.backup
scp /usr/local/nginx/conf/nginx.conf 192.168.45.128:/usr/local/nginx/conf
scp /usr/local/nginx/conf/nginx.conf 192.168.45.128:/usr/local/nginx/conf.backup
4.1.2 拷贝目录到远程服务器
命令格式： 拷贝目录
第一种方式：指定用户名，将目录远程拷贝到另外一台服务器的指定目录下，需要使用-r参数表示递归操作，命令执行后再输入密码
scp -r local_folder remote_username@remote_ip:remote_folder
第二种方式：不指定用户名，将目录远程拷贝到另外一台服务器的指定目录下，需要使用-r参数表示递归操作，命令执行后再输入密码
scp -r local_folder remote_ip:remote_folder
案例演示：
scp -r /tmp/ [email protected]:/
scp -r /tmp/ 192.168.45.128:/
4.2 从远程复制到本地服务器
从 远程复制到本地，只要将从本地复制到远程的命令的后2个参数 调换顺序即可，一起来看下。
4.2.1 远程服务器的文件拷贝到本地
第一种方式：指定远程用户名@指定IP:要复制的文件到./，这里./表示将远程服务器上的文件拷贝到本地服务器的当前路径。
scp remote_username@remote_ip:remote_file ./
第二种方式：指定远程用户名@指定IP:要复制的文件到本地服务器指定用户名，指定目录等
scp remote_username@remote_ip:remote_file local_username@local_ip:local_folder
案例演示：
scp [email protected]:/usr/local/nginx/conf/nginx.conf
/usr/local/conf/
scp -r [email protected]:/usr/local/nginx/ [email protected]:/usr/local/
当然也可以拷贝目录，方法还是一样在前面加-r参数，这里就不再演示。
除了可以选择IP来拷贝文件，还可以使用主机名进行拷贝，前提需要先将hostname做hosts映射。
cat /etc/hosts
192.168.45.166 localhost166
192.168.45.128 localhost128
scp -r root@localhost128:/usr/local/nginx/ root@localhost166:/usr/local
总结
scp命令也是经常会需要用到的，只需要了解从本地到远程，或从远程到本地的是如何使用即可，若觉得以上内容还行，可以点赞支持一下！
