Hi Jayd512,
sorry for inconvience, my aim was not to give clue to somebody of how to crack passwords.
I just wondered about using expect scripts. Unfortunatelly you can easy abuse those information for cracking passwords. I really needed those information for "password cracking"
(but all in therms of legal - I needet to automate process of password guessing on server in our company because of old admin set passwords and forgot which password on which server .
Although thanks for warning I will try not to post similar posts.




Thank you very much Vryali, you post helped me to move big step forward. You can be calm I did not abuse those information, just needed them all in therms of legal (a lot of them I will be using to something completly different (automating interactive commands), but the ssh password prompting gives great oportunity to ask lot of expect examples)
I have some more questions (If you dont mind)

1. Seems like in example that You have posted "continue" and "exp_ontinue" performs the same action (they both works as a "goto" to "expect" statement from which was invoked (Correct me if I am wrong))
- also read in man pages tat "continue" acts like any other classic "continue" statement which is used eg. in awk also, read that it sets TCL_CONTINUE what does this mean practically ?
- so what is difference between continue and exp_continue ?

2. Is adding "-re" to "expect" necessary, I read somewhere that "-re" enables regular expression evaluating.

3. Is possible to supress any output of TCL instead of lines that I want explicitly printed on screen eg. with puts function ?
- I used redirection in spawning of ssh ("2>&1>/dev/null") but expect also outputs some text, here is some discussion probably regarding this question but is unclear to me
https://www.unix.com/shell-programmin...sword-arg.html


Following questions may be related:

4. Please look at following post https://www.unix.com/shell-programmin...cant-stop.html
In 1st post user "radioactive9" "expect" the following string: "~]$ " two times. He complains about infinite looping which seems logic to me (because of string "~]$ " matched above in code and '{send "passwd\r" ; exp_continue}' is invoked again ). How does frappa's suggested 'send "exit\r\r' help in this situation ?

- In another words if i expect two same strings, the first one (code above) is always matched ?
- Also in 4th post there are two "expect" and in both is the "default" branch, which "default" branch will be called ?


5. Previous questions points me to another question; how to face situation when I need to "expect" same string but in different circumstances ? The previous link (1st post) explains well what I mean. My guess is to use another "expect" in particular superior "expect" (One problem I see is how to jump to most superior code), one code for thousand examples.

Code:

# SOME CODE HERE
expect {
"~]$ " {send "passwd\r";  expect {
													"(current) UNIX password:" {send "Password\r" ; exp_continue}
													"New UNIX password:" {send "P@ssw0rd\r" ; exp_continue}
													"Retype new UNIX password:" {send "P@ssw0rd\r" ; exp_continue}
													"~]$ " {send "exit\r"}											
													
													# ??? HOW TO JUMP TO MOST SUPERIOR "expect" ???
													
													# 1st SOLUTION:
													# "~]$ " {send "exit\r"; "break;" }
													
													# 2nd SOLUTION
													# "~]$ " { send "exit\r"; }
													# default { break; }
											  }
		 }
}
# SOME CODE HERE

Is this correctapproach ?


6. You have said that expect uses "send" action as it sees matching pattern from "expect", so how to overcome situation where pattern matches but input is not desired (end expect after all "send" some string) ? Is this really treaten as error ? (expect will "send" another string after input will be requested - correct me if I am wrong)
- eg. can be some kind of sleep issued ?
- are there used any buffers ?



7. I found somewhere on internet "set timeout -1", "match_max 100000", or using "send --" or even "send -s" instead of classic "send". Also I found that "send_user" could be used to send any output to user, dont ou know some site where those functions are explained cause eg. "match_max" confuses me what does buffer size stands for ?


Thank you very much for yor help.