Shell Programming and Scripting

#!/usr/bin/expect

log_user 0 
set timeout 10 

spawn telnet IP PORT
send "exit\r"
expect eof

if {[string match *searched_string* $expect_out(buffer)]} {
        puts "Connection successful"
}

#!/usr/bin/expect --
set IP [lindex $argv 0]
set PORT [lindex $argv 1]
set timeout 2
set fail "Name or service not known"
set failx "localhost: bad port"
set failxx "Servname not supported"

proc eexit {} {
    exit 1
  }

if {[llength $argv] != 2} {
puts "usage: ./telnetcheck HOST PORT "
eexit
}

log_user 0
spawn telnet $IP $PORT

expect {
"*'^]'.*" { puts "\nConnection is Success\n"; exit }
"$fail" { puts "\nUnknown Host!!\n" ; eexit }
"$failx" { puts "\nBad Port!!\n" ; eexit }
"$failxx" { puts "\nBad Servername!!\n" ; eexit }
timeout { puts "\nTime Out is Over. Exiting..!\n" ; eexit }
"refused*" { puts "\nConnection is Fail!!\n" ; eexit }
}

# ./telnetcheck host 22 
Connection is Success

# nc -z localhost 22
Connection to localhost 22 port [tcp/ssh] succeeded!

# nc -z localhost 1-22
Connection to localhost 21 port [tcp/ftp] succeeded!
Connection to localhost 22 port [tcp/ssh] succeeded!