预期 SFTP 脚本在 bash 中不起作用

Question

I have created a shell script containing an expect script for getting a file from remote location. Everything works well, until some command is sent. Whether it is 'ls' or 'pwd' or any other command, the expect script ends abruptly. Could you guy help me out with this.

NOTE : Security is not a concern, hence not using Public keys.

#!/bin/ksh

FTPREMOTEPATH=/Inbox
FTPREMOTEFILENAME=test.CSV


/usr/bin/expect -f - <<EOFEXPECT1
set timeout 60
spawn sftp -oPort=1002 username@test.server.com
expect {
        default { exit 1}
        -re "failed|invalid password|Permission denied" {exit 2}
        "Connection closed" {exit 1}
        timeout {exit 1}
}

expect "Password:"
send "password\r"

expect {
        default {exit 1}
        -re "password|Enter password for " {puts "Incorrect Password"; exit 2}
        "sftp>" {send "cd $FTPREMOTEPATH \r"}
}

expect "sftp>"
send "pwd\r"

send "get $FTPREMOTEFILENAME \r";

EOFEXPECT1

In above script, the scripts end abruptly after sending cd $FTPREMOTEPATH.

Below is the Output :

$ ./test.sh
spawn sftp -oPort=1002 username@test.server.com
Enter password for username
Password:
sftp> cd /Inbox
sftp> $

Answer 1

Imagine you call a local restaurant, and say "get me some food" and then just hang up. What is the restaurant supposed to do?

When you wait for the sftp prompt, you're waiting for the food to be delivered.

I'd recommend 2 things:

1. before send "get ... change the timeout value to -1 -- that will help if it takes longer than 60 seconds to receive the file.
2. after you send "bye", expect eof -- that lets the sftp connection close gracefully.

Answer 2

The reason is that your Expect script has reached the end of the script, and therefore terminates the child (ftp) process before the ftp process has a chance to finish downloading the file.

Answer 3

Okay, Apparently i was missing expect "sftp>" {send "bye\\n"} , before EOF (EOFEXPECT1).

However, i would still be interested in knowing the significance of bye in expect script.

Here is the updated and working code :

#!/bin/ksh

FTPREMOTEPATH=/Inbox
FTPREMOTEFILENAME=test.CSV


/usr/bin/expect -f - <<EOFEXPECT1
set timeout 60
spawn sftp -oPort=1002 username@test.server.com
expect {
        default { exit 1}
        -re "failed|invalid password|Permission denied" {exit 2}
        "Connection closed" {exit 1}
        timeout {exit 1}
}

expect "Password:"
send "password\r"

expect {
        default {exit 1}
        -re "password|Enter password for " {puts "Incorrect Password"; exit 2}
        "sftp>" {send "cd $FTPREMOTEPATH \r"}
}

expect "sftp>"
send "pwd\r"

send "get $FTPREMOTEFILENAME \r";

expect "sftp>" {send "bye\n"}

EOFEXPECT1