sftp用法http://blog.sciencenet.cn/blog-803390-632223.html
1. 用sftp如何登录服务器
sftp 是一个交互式文件传输程式。它类似于 ftp, 但它进行加密传输，比FTP有更高的安全性。下边就简单介绍一下如何远程连接主机，进行文件的上传和下载，以及一些相关操作。
举例，如远程主机的 IP 是 192.168.0.1，用户名是kyu,在命令行模式下:
sftp kyu@192.168.0.1
默认端口号为22，如果是其他端口号，例如22806，则使用命令：
sftp -oPort=22806 kyu@192.168.0.1
回车提示输入密码。
进入提示符
sftp>
如果登陆远程机器不是为了上传下载文件，而是要修改远程主机上的某些文件。可以
ssh kyu@192.168.0.1 -p 22806（其实sftp就是ssh 的一个程式，-p指定端口号）
2. sftp从服务器上下载文件：
sftp> get /var/www/kyu/index.php /home/kyu/
这条语句将从远程主机的 /var/www/kyu/目录下将 index.php 下载到本地 /home/kyu/目录下。
3. sftp将本地文件上传到服务器
sftp> put /home/fuyatao/downloads/Linuxgl.pdf /var/www/fuyatao/
这条语句将把本地 /home/fuyatao/downloads/目录下的 linuxgl.pdf文件上传至远程主机/var/www/fuyatao/ 目录下。
4. 查看登录时的服务器和本机的当前目录：
你如果不知道远程主机的目录是什么样， pwd命令可以帮您查询远程主机的当前路径。查询本机当前工作目录 lpwd.
5. 其他命令：改变路径可以用cd ，改变本机路径可以用 lcd;
ls rm rmdir mkdir 这些命令都可以使用。同理调用本机都是加 l , 即 lls lrm.
要离开sftp，用exit 或quit、 bye 均可。详细情况可以查阅 man sftp.
如果觉得在命令行模式下不太方便，可以 sudo apt-get install gftp。在图形界面下操作就简便多了。
What is SFTP?
FTP, or "File Transfer Protocol" is a popular method of transferring files between two remote systems.
SFTP, which stands for SSH File Transfer Protocol, or Secure File Transfer Protocol, is a separate protocol packaged with SSH that works in a similar way over a secure connection. The advantage is the ability to leverage a secure connection to transfer files and traverse the filesystem on both the local and remote system.
In almost all cases, SFTP is preferable to FTP because of its underlying security features and ability to piggy-back on an SSH connection. FTP is an insecure protocol that should only be used in limited cases or on networks you trust.
Although SFTP is integrated into many graphical tools, this guide will demonstrate how to use it through its interactive command line interface.
How to Connect with SFTP
By default, SFTP uses the SSH protocol to authenticate and establish a secure connection. Because of this, the same authentication methods are available that are present in SSH.
Although passwords are easy to use and set up by default, we recommend you create SSH keys and transfer your public key to any system that you need to access. This is much more secure and can save you time in the long run.
Please see this guide to set up SSH keys in order to access your server if you have not done so already.
If you can connect to the machine using SSH, then you have completed all of the necessary requirements necessary to use SFTP to manage files. Test SSH access with the following command:
ssh username@remote_hostname_or_IP
If that works, exit back out by typing:
exit
We can establish an SSH connection and then open up an SFTP session using that connection by issuing the following command:
sftp username@remote_hostname_or_IP
You will connect the the remote system and your prompt will change to an SFTP prompt.
Getting Help in SFTP
The most useful command to learn first is the help command. This gives you access to a summary of the SFTP help. You can call it by typing either of these in the prompt:
help
?
This will display a list of the available commands:
Available commands:
bye Quit sftp
cd path Change remote directory to 'path'
chgrp grp path Change group of file 'path' to 'grp'
chmod mode path Change permissions of file 'path' to 'mode'
chown own path Change owner of file 'path' to 'own'
df [-hi] [path] Display statistics for current directory or
filesystem containing 'path'
exit Quit sftp
get [-Ppr] remote [local] Download file
help Display this help text
lcd path Change local directory to 'path'
. . .
We will explore some of the commands you see in the following sections.
Navigating with SFTP
We can navigate through the remote system's file hierarchy using a number of commands that function similarly to their shell counterparts.
First, let's orient ourselves by finding out which directory we are in currently on the remote system. Just like in a typical shell session, we can type the following to get the current directory:
pwd
Remote working directory: /home/demouser
We can view the contents of the current directory of the remote system with another familiar command:
ls
Summary.txt info.html temp.txt testDirectory
Note that the commands within the SFTP interface are not the normal shell commands and are not as feature-rich, but they do implement some of the more important optional flags:
ls -la
drwxr-xr-x 5 demouser demouser 4096 Aug 13 15:11 . drwxr-xr-x 3 root root 4096 Aug 13 15:02 .. -rw------- 1 demouser demouser 5 Aug 13 15:04 .bash_history -rw-r--r-- 1 demouser demouser 220 Aug 13 15:02 .bash_logout -rw-r--r-- 1 demouser demouser 3486 Aug 13 15:02 .bashrc drwx------ 2 demouser demouser 4096 Aug 13 15:04 .cache -rw-r--r-- 1 demouser demouser 675 Aug 13 15:02 .profile . . .
To get to another directory, we can issue this command:
cd testDirectory
We can now traverse the remote file system, but what if we need to access our local file system? We can direct commands towards the local file system by preceding them with an "l" for local.
All of the commands discussed so far have local equivalents. We can print the local working directory:
lpwd
Local working directory: /Users/demouser
We can list the contents of the current directory on the local machine:
lls
Desktop local.txt test.html Documents analysis.rtf zebra.html
We can also change the directory we wish to interact with on the local system:
lcd Desktop
Transferring Files with SFTP
Navigating the remote and local filesystems is of limited usefulness without being able to transfer files between the two.
Transferring Remote Files to the Local System
If we would like download files from our remote host, we can do so by issuing the following command:
get remoteFile
Fetching /home/demouser/remoteFile to remoteFile /home/demouser/remoteFile 100% 37KB 36.8KB/s 00:01
As you can see, by default, the "get" command downloads a remote file to a file with the same name on the local file system.
We can copy the remote file to a different name by specifying the name afterwards:
get remoteFile localFile
The "get" command also takes some option flags. For instance, we can copy a directory and all of its contents by specifying the recursive option:
get -r someDirectory
We can tell SFTP to maintain the appropriate permissions and access times by using the "-P" or "-p" flag:
get -Pr someDirectory
Transferring Local Files to the Remote System
Transferring files to the remote system is just as easily accomplished by using the appropriately named "put" command:
put localFile
Uploading localFile to /home/demouser/localFile localFile 100% 7607 7.4KB/s 00:00
The same flags that work with "get" apply to "put". So to copy an entire local directory, you can issue:
put -r localDirectory
Note
There is currently a bug in the versions of OpenSSH shipped with current Ubuntu releases (at least 14.04 to 15.10) that prevents the above command from operating correctly. Upon issuing the command above to transfer content to a server using the buggy version of OpenSSH, the following error will be given: Couldn't canonicalise: No such file or directory.
To work around this issue, create the destination directory on the remote end first by typing mkdir localDirectory. Afterwards, the above command should complete without error.
One familiar tool that is useful when downloading and uploading files is the "df" command, which works similar to the command line version. Using this, you can check that you have enough space to complete the transfers you are interested in:
df -h
Size Used Avail (root) %Capacity 19.9GB 1016MB 17.9GB 18.9GB 4%
Please note, that there is no local variation of this command, but we can get around that by issuing the "!" command.
The "!" command drops us into a local shell, where we can run any command available on our local system. We can check disk usage by typing:
! df -h
Filesystem Size Used Avail Capacity Mounted on /dev/disk0s2 595Gi 52Gi 544Gi 9% / devfs 181Ki 181Ki 0Bi 100% /dev map -hosts 0Bi 0Bi 0Bi 100% /net map auto_home 0Bi 0Bi 0Bi 100% /home
Any other local command will work as expected. To return to your SFTP session, type:
exit
You should now see the SFTP prompt return.
Simple File Manipulations with SFTP
SFTP allows you to perform the type of basic file maintenance that is useful when working with file hierarchies.
For instance, you can change the owner of a file on the remote system with:
chown userID file
Notice how, unlike the system "chmod" command, the SFTP command does not accept usernames, but instead uses UIDs. Unfortunately, there is no easy way to know the appropriate UID from within the SFTP interface.
An involved work around could be accomplished with:
get /etc/passwd !less passwd
root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/bin/sh bin:x:2:2:bin:/bin:/bin/sh sys:x:3:3:sys:/dev:/bin/sh sync:x:4:65534:sync:/bin:/bin/sync games:x:5:60:games:/usr/games:/bin/sh man:x:6:12:man:/var/cache/man:/bin/sh . . .
Notice how instead of giving the "!" command by itself, we've used used it as a prefix for a local shell command. This works to run any command available on our local machine and could have been used with the local "df" command earlier.
The UID will be in the third column of the file, as delineated by colon characters.
Similarly, we can change the group owner of a file with:
chgrp groupID file
Again, there is no easy way to get a listing of the remote system's groups. We can work around it with the following command:
get /etc/group !less group
root:x:0: daemon:x:1: bin:x:2: sys:x:3: adm:x:4: tty:x:5: disk:x:6: lp:x:7: . . .
The third column holds the ID of the group associated with name in the first column. This is what we are looking for.
Thankfully, the "chmod" command works as expected on the remote file system:
chmod 777 publicFile
Changing mode on /home/demouser/publicFile
There is no command for manipulating local file permissions, but you can set the local umask, so that any files copied to the local system will have the appropriate permissions.
That can be done with the "lumask" command:
lumask 022
Local umask: 022
Now all regular files downloaded (as long as the "-p" flag is not used) will have 644 permissions.
SFTP allows you to create directories on both local and remote systems with "lmkdir" and "mkdir" respectively. These work as expected.
The rest of the file commands target only the remote filesystem:
ln rm rmdir
These commands replicate the basic behavior of the shell versions. If you need to perform these actions on the local file system, remember that you can drop into a shell by issuing this command:
!
Or execute a single command on the local system by prefacing the command with "!" like so:
!chmod 644 somefile
When you are finished with your SFTP session, use "exit" or "bye" to close the connection.
bye
Conclusion
Although SFTP is a simple tool, it is very useful for administrating servers and transferring files between them.
If you are used to using FTP or SCP to accomplish your transfers, SFTP is a good way to leverage the strengths of both. While it is not appropriate for every situation, it is a flexible tool to have in your repertoire.
来源：oschina
链接：https://my.oschina.net/u/2308739/blog/705404