Shell Programming and Scripting

Hi,
I got an issue in .netrc , please find below SFTP script and .netrc file .
getting error as below, please assist me to rectify, thanks.

Code:

sftp> $ imuploaddata test1.DAT /home/test/
Invalid command.

FTP scripts

Code:

abc@systalk:~/test> cat imftp.sh
#!/bin/sh
filetoftp="$1"
filepath="$2"
echo "\$ imuploaddata $filetoftp $fi

.netrc macro

Code:

abc@systalk:~/test> cat ../.netrc

# machine MVS2.MAS.NET login TS19610 password ihsan31
machine s_kulsznas1.kulsz.usr.mas.net login kulsz/\graflite password grafl1te
machine 10.251.21.157 login sysftp password imsw19tp
macdef imupload1
        cd /PROJECT_D/01_source_layer/01_raw_source_files/CPD
        lcd $2
        prompt off
        ascii
        verbose on
        put $1
        quit

macdef imuploaddata
        cd /PROJECT_B/01_source_layer/01_raw_source_files/CPD
        lcd $2
        prompt off
        ascii
        verbose on
        put $1
        quit

The .netrc file is generally used for FTP connection credentials etc., however you seem to want to use sftp which is another thing altogether.

SFTP uses files in (typically) ~/.ssh to store all sorts of things but it's quite different to plain FTP so you can't just copy things around.

More usually you would create a batch file of commands you want SFTP to perform and call them with a -b flag. You would need to either answer login prompts or create an SSH key pair, putting the public key on the target server.


How much do you know about SFTP use, authentication, etc.?



Robin

Hi rbatte1,
Thank you very much for the clarification that .netrc doesnt support netrc.

my understanding is on SFTP is only that he its a secure FTP and and works on port 22 instead of 21.

here can you please explain how best i can convert below codes in order to work with SFTP.

Thank you.

Whilst the general commands within sftp are very similar (get, put, rename, chmod etc.) the mechanism is very different. The connection is designed to be secure, so you cannot force a user & password into it like this:-

Code:

sftp <<-EOSFTP
$userid $password
get file
quit
EOSFTP

....or other forms of pushing input into tools. SSH & similar tools have been designed with their own way of working, the exchange of encryption keys. More goes on than you need to know but the important bits for most of us are that the credentials are generated by the client side in the form of two keys. The private one remains on the client side and is used for decrypting the incoming data, and the public key can be shared around.

If a server has a public key (or multiple public keys) stored in the correct place in a secure manner, the owner of the private key is able to connect with a passphrase. Often, for automated tasks, this passphrase is null so the login becomes automatic.

The process to follow to set this up would be:-
The public keys are used to encrypt the data and the private keys are used to decrypt it, but this then becomes automatic from your point of view.

After you can open an ssh connection, you should be able to use sftp in your script. Depending on how complex your needs, you might be able to use a here document like this:-

Code:

sftp $user@$server <<END
get remote-file local-file
END

....or you could create a batch file like this:-

Code:

$ cat simple.batch
get remote-file local-file
$ sftp -b simple.batch  $user@$server

Have a go, and let us know if you get stuck. I have probably missed something or not explained it clearly so it probably won't work first time. I must say that I have never used macdef so I'm not sure how this could be written, but there are bound to be options.


I hope that this helps,
Robin

It's an entirely different protocol, ssh, emulating FTP for convenience's sake.

What it does not -- will not -- cannot do, is use stored passwords. It intentionally does not support .netrc, or passwords over pipe, or passwords over commandlne, or passwords over environment, or any other insecure way of storing passwords. This is a security feature. This breaks a lot of designs of old - a lot of bad, insecure designs of old.

You have to generate a set of key files in advance, and share them with the server, before you can noninteractively login instead.