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I have script where I put scp command to backup file to other server. But when it runs it asking to type password. Is there way to automate this? I am using CentOS 5.6. I have seen few guides they use spawn command when I use it, its saying -bash: spawn: command not found.

#!/usr/bin/expect -f

# connect via scp
spawn scp "user@example.com:/home/santhosh/file.dmp" /u01/dumps/file.dmp
expect {
-re ".*es.*o.*" {
exp_send "yes\r"
-re ".*sword.*" {
exp_send "PASSWORD\r"
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up vote 3 down vote accepted

Make sure you have 'Expect' installed. In Linux distributions with 'yum', run (as root): # yum install expect Then make sure the path to expect is correct in your script by typing: $ which expect /usr/bin/expect The path returned is to be put in the beginning of the script at #!/usr/bin/expect -f

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it was already installed (expect-5.43.0-5.1.i386) and path was correct yet still not working, maybe i call script incorrectly it i do "bash <script name>"? – Hujeplet Dec 9 '11 at 19:49
Works when i use chmod +x file.sh and run as ./file.sh – Hujeplet Dec 9 '11 at 19:55
Cool then, yeah #! is a general notation to execute as script under another interpreter/program and it needs the file to be executable unless the file is directly passed to the program as an argument to execute the instructions in the file. – Nikhil Mulley Dec 9 '11 at 19:57
One more question can i use timestamp in filename somehow e.g. "date"; – Hujeplet Dec 9 '11 at 20:41
yes, its possible. declare a variable, assign the date value but in the string format to it and then use the stringified date variable. – Nikhil Mulley Dec 9 '11 at 20:48

Use key based authentication with empty passphrase. This will not ask for password.

Follow these steps.

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cant use key authentication because server i scp to is shared and they dont let me install it – Hujeplet Dec 9 '11 at 19:42
Alright, so you do not have other option than using expect. – Sachin Divekar Dec 9 '11 at 19:47
yes, but i found answer already thanks though – Hujeplet Dec 9 '11 at 19:57
You don't need to install anything on the destination server - just copy over a file (...using scp itself). Use the ssh-copy-id command to copy the key file over - it simply creates a file ~/.ssh/authorized_keys with your public key. Everything should work automatically from there. – lutzky Dec 10 '11 at 9:33

If spawn is not working, you need to check your expect installation. Sending password can be automated like this...

spawn scp "user@example.com:/home/santhosh/file.dmp" /u01/dumps/file.dmp

expect {
"assword:" {
    send "MyPassword\r"
    # you can send remote commands here..
"yes/no)?" {
    send "yes\r"
    sleep 2
timeout {
    puts "\nError: timed out.\n"
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