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Problem with capturing output from mkpasswd

Posted by magna777 (magna777), 25 September 2004
I'm new to the expect language.  I have an expect script that that  takes in two command line arguments - host and account name.   The purpose of the script is to ssh to a certain host and create a new account on that host.   The password for this new account is automatically generated within this script.  The problem I'm having is capturing the output from the expect command "mkpasswd" which is called in my script and using the generated password.   Anyone's input would be greatly appreciated.  Here is my code:

#!/usr/local/bin/expect -f

if { $argc != 2 } {
  send_user "Usage: $argv0  host  emailAccountNameToCreate\n"
  exit 1
}

set timeout 5

set env(TERM) vt100;# actual value doesn't matter, just has to be set

set host [ lindex $argv 0 ]

set account [ lindex $argv 1 ]

spawn mkpasswd -l 9 -C 3 -c 3

expect eof

set password $expect_out( buffer )

spawn ssh root@$host

set value 1

while { $value } {
  global value

  expect "password:" { send "jus4Us\n"; set value 0 } \
             "(yes/no)?" { send "yes\n" } \
             timeout     { send_user "Timed out trying to connect to $host\n"; exit 1 }
}

expect "root]#" { send "adduser $account\n" } \
           timeout  { send_user "Timed out waiting for the system prompt during the step: adduser $account\n"; exit 1 }

expect "$account exists" { send_user "That account name already exists on $host\n"; exit 1 } \
           "root]#"          { send "passwd $account\n" } \
           timeout           { send_user "Timed out waiting for the system prompt during the step: passwd $account\n"; exit 1 }

expect "password:" { send "$password\n" } \
           timeout     { send_user "Timed out waiting for the system to prompt for a new password\n"; exit 1 }

expect "password:" { send "$password\n" } \
           timeout     { send_user "Timed out waiting for the system to ask to retype new password\n"; exit 1 }

send_user "mkpasswd generated: $password\n"
exit 0





When I try running this script I get the following error:

can't read "expect_out( buffer )": no such element in array
   while executing


Posted by admin (Graham Ellis), 25 September 2004
I think your problem is the spaces around the word "buffer". I cut and pasted your script, reduced it to this and reproduced the failure:

Code:
#!/usr/bin/expect -f

spawn mkpasswd -l 9 -C 3 -c 3
expect eof
set password $expect_out( buffer )
puts $password


I then removed the spaces so it read like this

Code:
#!/usr/bin/expect -f

spawn mkpasswd -l 9 -C 3 -c 3
expect eof
set password $expect_out(buffer)
puts $password


and the code worked

Posted by magna777 (magna777), 25 September 2004
Thanks so much Graham!  I cannot beleve it was that simple.  But I am beginning to notice that expect is very particular!  Thanks again bud!



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