what does interact do with terminals?

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Aiming Xu
2010-11-03
2013-05-02
  • Aiming Xu
    Aiming Xu
    2010-11-03

    hi,
    Nice to see you guys here.
    what i am doing is all about 'interact' with expect.
    A simple example that i used putty/securecrt login to A where the expect script  lies on.
    the script is simple , just telnet to another computer B and then interact so that i can do sth about B.
    what i wanna do is type a command with long arguments, the argument so long that it would be printed in the next line.
    at the very beginning, the expect script  worked fine, but when i resized the terminal(putty/securecrt) window, sth interesting happened:I print a very long argument which would have to be shown in the next line, but when the character hit the end of  the first line, it started form the beginning of the SAME line instead of next line, all the original characters lied at the beginning of the line were covered one by one with new typed characters.
    its really, so i was wondering how does 'interact' affect terminal buffer, what happened inside 'interact' when i resized the window of the terminal.
    or is there a way to solve this problem, so that when the character hit the end of the line it will start from next line no matter whether i resize the window or not.
    any hlp would be appreciated.
    Aimng
    2010-11-03

     
  • ender
    ender
    2010-11-03

    Interact is supposed to just pass characters between the user and the spawned process.
    It might be a problem with cooked mode vs raw mode.
    Try interact -reset

     
  • Aiming Xu
    Aiming Xu
    2010-11-04

    still doesn't work.
    if i logged in directly with putty/securecrt there wasn't a problem.
    but when it went through expect,strange things occurred.
    code clip:

    114         set user
    115         set pwd1
    116         set pwd2
    117         if { $user != "" } {
    118             spawn -noecho $ssh -l $user -p $port $ip
    119             if { $pwd1 != "" } {
    120                 expect {
    121                     eof         {puts "<ERROR:EOF>"}
    122                     timeout     {puts "<ERROR:TIMEOUT>"}
    123                     "assword:"  {
    124                         send "$pwd1\r"
    125                         if { $pwd2 != "" } {
    126                             expect {
    127                                 eof         {puts "<ERROR:EOF>"}
    128                                 timeout     {puts "<ERROR:TIMEOUT>"}
    129                                 "]$ "       {
    130                                     send "su\r"
    131                                     expect  {
    132                                         eof         {puts "<ERROR:EOF>"}
    133                                         timeout     {puts "<ERROR:TIMEOUT>"}
    134                                         "assword:"  {
    135                                             send "$pwd2\r"
    136                                         }
    137                                     }
    138                                 }
    139                             }
    140                         }
    141                     }
    142                 }
    143             }
    144         } else {
    145             spawn -noecho $ssh -p $port $ip
    146         }
    147         interact
    148         exit 0
    this is ssh login, but the problem is the same, very inelegant.will it be the problem with spawn? if it is, what can i do to get any hlp about it?
    any hlp would be really appreciated.
    Aiming

     
  • ender
    ender
    2010-11-05

    I tried on my system and can't duplicate it using putty and ssh into another system. So the only things I can think of are
    try without the -noecho
    Maybe it's the terminal settings on the server you're ssh'ing into that is causing problems.
    Get the book exploring expect which has a lot of information on the options for spawn and interact plus details on how it works
    Or maybe not use expect for this. Since you're using ssh why not use keys so you can skip the login process.

    Sorry couldn't help more. Good luck.

     
  • Aiming Xu
    Aiming Xu
    2010-11-08

    I didn't deal with the signal SIGWINCH.
    now add:
    trap {
            set rows
            set cols
            stty rows $rows columns $cols < $spawn_out(slave, name)
    }WINCH
    It works now LOL.
    Thank you ender21014, god luck to you.
    Aiming

     
  • ender
    ender
    2010-11-08

    Excellent. Thank you for the information on making it work.