Filetransfer via SSH (terminal) on Linux/Unix

SSH File Transfers

Though FTP has been commonly used in the School of Computing and by many other sites across the globe, it suffers a severe lack of security by passing a user's login information, including their password, via plain text across the network. In order to avoid such a blatent security hole, we are using the encrypted SSH protocol for logins and file transfers. This document is meant to be a quick guide on using SSH/SFTP for file transfers on UNIX and Windows machines. Note: MacOSX users, via the Terminal application, can use the command line to perform file transfers, as UNIX systems are described below. Note: To use SSH/SFTP from an SoC Facility UNIX machine, You will need /uusoc/bin in your PATH environment variable to access the programs mentioned in this guide. Unix - Unix Transferring files between two Unix systems using SSH is handled by two simple command line programs, scp and sftp. SCP I'm using SCP, for saving transfer time, If you have a few files or big files to transfer, you can save time by using the scp command instead of sftp. scp works much like rcp, for those who are familiar with the remote shell tools. All interaction is handled on the command line. File transfers can be done in either direction. Using the same files from our example above, transferring them using scp would work like this: > scp "remotemachine:/server/homework/*.txt" . myfile1.txt | 3 KB | 3.3 kB/s | ETA: 00:00:00 | 100% myfile2.txt | 0 KB | 0.8 kB/s | ETA: 00:00:00 | 100% myfile3.txt | 6 KB | 6.3 kB/s | ETA: 00:00:00 | 100% >   or something like this   $ sudo scp "user@remote:/from/public/dir\ some\ place\ you\ have/*" toyourdir/  user@remote's password:   Notice that the wildcard listing for the remote machine must be in double quote marks for the string to be passed correctly. The period at the end of the line tells scp to copy the files to the current directory of the local machine. Of course, you can specify any local directory that you can write to, like /tmp or /tmp/mydir or ./mydir. Transferring files to a remote machine is done in much the same way: > scp *.txt remotemachine:. myfile1.txt | 3 KB | 3.3 kB/s | ETA: 00:00:00 | 100% myfile2.txt | 0 KB | 0.8 kB/s | ETA: 00:00:00 | 100% myfile3.txt | 6 KB | 6.3 kB/s | ETA: 00:00:00 | 100% > Note that the wildcard string does not need quotes when specifying files on the local machine. Also, the remotemachine:." tells scp to use your home directory on the remote system. Again, you can use any directory you can write to, like remotemachine:/tmp   SFTP As the name might imply, sftp works much like a regular ftp client, but transfers are all made across an encrypted channel. To establish a secure ftp connection to a machine, simply use:  sftp You will be prompted for your password/passphrase and then dropped into an ftp-like prompt. Typing a "?" at the prompt will show you supported commands. sftp> ? Available commands: cd path Change remote directory to 'path' lcd path Change local 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' help Display this help text get remote-path [local-path] Download file lls [ls-options [path]] Display local directory listing ln oldpath newpath Symlink remote file lmkdir path Create local directory lpwd Print local working directory ls [path] Display remote directory listing lumask umask Set local umask to 'umask' mkdir path Create remote directory put local-path [remote-path] Upload file pwd Display remote working directory exit Quit sftp quit Quit sftp rename oldpath newpath Rename remote file rmdir path Remove remote directory rm path Delete remote file symlink oldpath newpath Symlink remote file version Show SFTP version !command Execute 'command' in local shell ! Escape to local shell ? Synonym for help sftp> Navigation through directories is that same as with a standard shell, ls, cd, rm, et cetera. cd will change your working directory on the remote machine and lcd will change your working directory on your local system. The actual file transfer process is handled with the get and put commands. For our example, lets say that you want to grab a couple of files off of a remote Unix machine, which are located in /server/homework. Once you have connected and entered your password, you would simple use: cd /server/homework to reach the desired directory. Using the ls command will show you the files within. sftp> ls myfile1.txt myfile2.txt myfile3.txt sftp> In order to transfer these files to your local machine, you would use get and then the names of the files you wish to transfer. Standard Unix wildcards apply. For example: sftp> get *.txt myfile1.txt:.................................................................. 3397 bytes received in 0.03 secs, 104.90 K/s myfile2.txt:.................................................................. 791 bytes received in 0.01 secs, 56.70 K/s myfile3.txt:.................................................................. 6441 bytes received in 0.02 secs, 219.65 K/s sftp> sftp will show you the size of the files transfered and how long it took for each file. The put command will transfer files from your local machine to the remote system in much the same way. Users familiar with standard ftp clients might be a little confused about selecting "binary" or "ASCII" transfer mode. Don't worry about it, binary mode is the only mode that sftp supports, the commands are simply there as legacy. . Please refer to the man pages for sftp and scp references beyond the scope of this guide.