Shell Programming and Scripting

SU-capitan:/home/unix/wakatana# ssh strom
This server is production server

wakatana's password: [TYPING CORRECT PASSWORD "unix"]
Authentication successful.
Your password has expired.  You are now forced to change it.
Last login: Fri Jul 27 2012 15:24:13 +0100 from capitan
Sun Microsystems Inc.   SunOS 5.10

Please note the following:
This server is production server

TERM = (unknown) [TYPED "xterm" AND PRESSED ENTER]
[SCREEN CLEARS AND SHELL APPEARS AS EXPECTED]
strom:/home/unix/wakatana$

SU-capitan:/home/unix/wakatana# ssh strom
This server is production server

wakatana's password:
wakatana's password:
wakatana's password:
warning: Authentication failed.
Disconnected; no more authentication methods available (No further authentication methods available.).
SU-capitan:/home/unix/wakatana#

SOURE CODE:
-------------
#!/usr/local/bin/expect
set pass1 "unix1\n";
set pass2 "unix2\n";
set pass3 "unix\n";
set machine [lindex $argv 0];

spawn ssh -q "${machine}" "exit";
expect {
            -re "(P|p)assword:" {send ${pass1}; puts ${pass1}}
            -re "(P|p)assword:" {send ${pass2}; puts ${pass2}}
            -re "(P|p)assword:" {send ${pass3}; puts ${pass3}}
}
interact;


RESULT1:
---------
SU-capitan:/home/unix/wakatana# ./tcl1.tcl strom # pass1 contains WRONG pass
spawn ssh -q strom exit
wakatana's password: unix1

wakatana's password: [AT THIS POINT IT HANGS AND PRESSING ENTER IS REQUIRED]
wakatana's password: [AT THIS POINT IT HANGS AND PRESSING ENTER IS REQUIRED]


RESULT2:
---------
SU-capitan:/home/unix/wakatana# ./tcl1.tcl strom # pass1 contains CORRECT pass
spawn ssh -q strom exit
wakatana's password: unix

unix

Your password has expired.  You are now forced to change it.
TERM = (unknown) [TYPED "xterm" AND PRESSED ENTER]
[SCREEN CLEARS AND SHELL APPEARS AS EXPECTED]

SOURCE CODE:
--------------
#!/usr/local/bin/expect
set pass1 "unix\n";

set machine [lindex $argv 0];

spawn ssh -q "${machine}" "exit" ;
expect {
                -re "(P|p)assword:" { send ${pass1}; exp_continue}
}
            
puts "PASSWORD: ${pass1}"
interact;

RESULT1:
---------
SU-capitan:/home/unix/wakatana# ./tcl2.tcl strom # pass1 contains correct pass
spawn ssh strom exit
This server is production server

wakatana's password:
Authentication successful.
Your password has expired.  You are now forced to change it.
PASSWORD: unix

spawn_id: spawn id exp4 not open
    while executing
"interact"
    (file "./tcl2.tcl" line 13)
SU-capitan:/home/unix/wakatana#

SOURCE CODE:
--------------
#!/usr/local/bin/expect
set pass1 "unix\n";
set machine [lindex $argv 0];

spawn ssh -q "${machine}" "exit" ;
expect {
                -re "(P|p)assword:" { send ${pass1}; puts "PASSWORD: ${pass1}"; exp_continue}
}
interact;


RESULT:
--------
SU-capitan:/home/unix/wakatana# ./tcl3.tcl strom
spawn ssh -q strom exit
wakatana's password: PASSWORD: unix


Your password has expired.  You are now forced to change it.
spawn_id: spawn id exp4 not open
    while executing
"interact"
    (file "./tcl3.tcl" line 11)

SOURCE CODE:
--------------
#!/usr/local/bin/expect
global var "";
set pass1 "unix1\n";
set pass2 "unix\n";
set pass3 "unix2\n";
set machine [lindex $argv 0];

spawn ssh -q "${machine}" "exit" ;
expect {

            
            -re "(P|p)assword:" {
            send ${pass1};
            #puts ${pass1};
            set var ${pass1};
            expect {
                        -re "(P|p)assword:" {
                        send ${pass2};
                        #puts ${pass2};
                        set var ${pass2};
                        expect {
                        -re "(P|p)assword:" {
                        send ${pass3};
                        #puts ${pass3};
                        set var ${pass3};
                        }
                        }
                        }
            }
            }
}
puts "CORRECT PASSWORD IS: ${var}"
interact;




RESULT:
--------
SU-capitan:/home/unix/wakatana# ./tcl4.tcl strom
spawn ssh -q strom exit
wakatana's password:
wakatana's password:
Your password has expired.  You are now forced to change it.
CORRECT PASSWORD IS: unix

spawn_id: spawn id exp4 not open
    while executing
"interact"
    (file "./tcl4.tcl" line 33)

1. How does expect knows when is typing of input possible (when I can invoke send) ?

eg. Is expect capable to process also text that appears on screen but (user) input is not expected (in normal circumstances) ?
- or in other words, how expect know if app has input available or requires user interaction or what is the correct name

2. Does TCL=Expect ?
- or expect uses TCL ?

3. Does expect supports some kind of looping
- eg. If same text appears on screen which will match "expect" pattern (requesting password) the different "send" action will be called (passing next element from array)?
- in other words: How to "expect" same pattern for several times but "send" another string

4. Does expect supports something opposite to regexp, or negation of regexp ?
- eg. expecting some string in loop and calling send (passing password) but do another action if expect wont match string (password was guessed or chances expired)
- in other words: How to "expect" same pattern for several times and "send" another string but after not matching "expect"

            spawn ssh ${SSHOpts} ${UserName}@${server}
            expect {
                "timed out" {
                    logWrite ${oFile} ${server} "ERROR: Timed out"
                    continue
                }
                "reset by peer" {
                    logWrite ${oFile} ${server} "ERROR: Connection reset"
                    continue
                }
                "failure in name resolution" {
                    logWrite ${oFile} ${server} "ERROR: Host not found"
                    wait
                    continue
                }
                "(yes/no)?" {
                    send "yes\r"
                    exp_continue
                }
                "*word:" {
              ..........

5. In my situation, when I just want to know right password (connecting to server and after exiting) is command "interact" (or statement or whatever it is called) required ?

6. What exactly does exp_continue doing ? It seems like if it wont wait for requested input until "send" is invoked, is there some timeout or something similar ?
- eg. is possible to invoke "exp_continue" to repeat "send" but with different arguments and when "expect" wont match the exp_continue will break ?

7. Is possible to do some basic if else construction in input matching (in "expect")
- I would also handle following message "continue connecting yes/no"

# 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