how to pass password to sftp connection in shell script

Try with this below option,

lftp -u $user,$pass sftp://$host << --EOF--
cd $directory
put $srcfile
quit

--EOF--

You could use ~/.ssh/config file.

#
# ~/.ssh/config
#

Host servername
Hostname 127.127.127.127
Port 22
User root

#EOF: config

Then simply connect with "ssh servername" and if you don't want to use password you can use SSH key. Here is good tutorial on how to do that > http://www.cyberciti.biz/tips/linux-multiple-ssh-key-based-authentication.html

If you just want to pass user/server from terminal, you can do this.

#!/bin/bash
sftp -b "$1"@"$2"

then use it like this './sftp.sh user server'

use SCP like this;

scp -P 22 user@server:/dir/file.tgz ~/Desktop/

use SFTP like this;

sftp user@server:/dir/file.tgz ~/Desktop/file.tgz

You can also try this;

sftp user@host <<EOF
get /dir/file.tgz
rm /dir/file.tgz
EOF

The best way to do this would be to create a key pair on the client, and add the key to the target user's ~/.ssh/authorized_keys.

To create a key pair, run ssh-keygen and when it asks for a password, just hit return to indicate "no password". Then either run ssh-copy-id $user@$server_name or manually create a ~/.ssh/authorized_keys on the server and copy the contents of the ~/.ssh/id_rsa.pub from the client into it (ssh-copy-id isn't available on all machines, so on some you'll have to do it manually).

Now you should be able to run ssh or scp without a password, as it should use your key instead. If it doesn't work, make sure that the permissions on your ~/.ssh/ directory and contents are correct on both machines; the directory should be 0700 (drwx------) and the files should be 600 (-rw-------). Also check that key authentication is enabled on both the client and the server.