Creating a script for a Telnet session? - scripting

Does anyone know of an easy way to create a script that can connect to a telnet server, do some usual telnet stuff, and then log off? I am dealing with users who are not familiar with telnet and the commands they will need to run. All I want is for them to double-click on a script, and have that script automatically execute the commands for them.
You're probably wondering, "What platform are the users on?" They will be on both Windows and Linux. Implementations in languages like Perl, Java, or Python are acceptable. I see that Perl has a Net:: Telnet module. Has anyone used that?
My ideal solution would be to create two script files. a BAT file for windows, and a shell script for Linux. While this would make dual maintenance an issue, it would mean I wouldn't have to install Perl/Java/Python/etc... on every machine. Unfortunately, I have not seen any way to automate a telnet session with batch files or shell scripts.
Thanks.

I've used various methods for scripting telnet sessions under Unix, but the simplest one is probably a sequence of echo and sleep commands, with their output piped into telnet. Piping the output into another command is also a possibility.
Silly example
(echo password; echo "show ip route"; sleep 1; echo "quit" ) | telnet myrouter
This (basically) retrieves the routing table of a Cisco router.

Expect is built for this and can handle the input/output plus timeouts etc. Note that if you're not a TCL fan, there are Expect modules for Perl/Python/Java.
EDIT: The above page suggests that the Wikipedia Expect entry is a useful resource :-)

Another method is to use netcat (or nc, dependent upon which posix) in the same format as vatine shows or you can create a text file that contains each command on it's own line.
I have found that some posix' telnets do not handle redirect correctly (which is why I suggest netcat)

This vbs script reloads a cisco switch, make sure telnet is installed on windows.
Option explicit
Dim oShell
set oShell= Wscript.CreateObject("WScript.Shell")
oShell.Run "telnet"
WScript.Sleep 1000
oShell.Sendkeys "open 172.25.15.9~"
WScript.Sleep 1000
oShell.Sendkeys "password~"
WScript.Sleep 1000
oShell.Sendkeys "en~"
WScript.Sleep 1000
oShell.Sendkeys "password~"
WScript.Sleep 1000
oShell.Sendkeys "reload~"
WScript.Sleep 1000
oShell.Sendkeys "~"
Wscript.Quit

It may not sound a good idea but i used java and used simple TCP/IP socket programming to connect to a telnet server and exchange communication. ANd it works perfectly if you know the protocol implemented. For SSH etc, it might be tough unless you know how to do the handshake etc, but simple telnet works like a treat.
Another way i tried, was using external process in java System.exec() etc, and then let the windows built in telnet do the job for you and you just send and receive data to the local system process.

Check for the SendCommand tool.
You can use it as follows:
perl sendcommand.pl -i login.txt -t cisco -c "show ip route"

import telnetlib
user = "admin"
password = "\r"
def connect(A):
tnA = telnetlib.Telnet(A)
tnA.read_until('username: ', 3)
tnA.write(user + '\n')
tnA.read_until('password: ', 3)
tnA.write(password + '\n')
return tnA
def quit_telnet(tn)
tn.write("bye\n")
tn.write("quit\n")

Couple of questions:
Can you put stuff on the device that you're telnetting into?
Are the commands executed by the script the same or do they vary by machine/user?
Do you want the person clicking the icon to have to provide a userid and/or password?
That said, I wrote some Java a while ago to talk to a couple of IP-enabled power strips (BayTech RPC3s) which might be of use to you. If you're interested I'll see if I can dig it up and post it someplace.

I like the example given by Active State using python. Here is the full link. I added the simple log in part from the link but you can get the gist of what you could do.
import telnetlib
prdLogBox='142.178.1.3'
uid = 'uid'
pwd = 'yourpassword'
tn = telnetlib.Telnet(prdLogBox)
tn.read_until("login: ")
tn.write(uid + "\n")
tn.read_until("Password:")
tn.write(pwd + "\n")
tn.write("exit\n")
tn.close()

Bash shell supports this out-of-box, e.g.
exec {stream}<>/dev/tcp/example.com/80
printf "GET / HTTP/1.1\nHost: example.com\nConnection: close\n\n" >&${stream}
cat <&${stream}
To filter and only show some lines, run: grep Example <&${stream}.

Write the telnet session inside a BAT Dos file and execute.

Related

Automatic answer (input) in PuTTY

Is there any way to provide answers (input) to commands executed in PuTTY?
Lets say I have a PuTTY session named TEST and I want to start the session with some commands stored in putty.cmd file. After triggering some functions it expects an option to select, so how can I automate the response
Ex: When I trigger phone command it gives option like
Initiate a call
Send SMS
Quit
I have to select an option.
putty.cmd has just one line
./phone
echo 2 (this didn't enable option 2)
Is there any way to select that option?
For automation, use Plink (from PuTTY package). It's a console equivalent of PuTTY. So it supports input redirection:
(
echo ./phone
echo 2
) | plink username#example.com
Though the correct option would be to find out, if the command (phone) accepts some arguments/switches to select the options you want to use.

Read all lines at the same time individually - Solaris ksh

I need some help with a script. Solaris 10 and ksh.
I Have a file called /temp.list with this content:
192.168.0.1
192.168.0.2
192.168.0.3
So, I have a script which reads this list and executes some commands using the lines values:
FILE_TMP="/temp.list"
while IFS= read line
do
ping $line
done < "$FILE_TMP"
It works, but it executes the command on line 1. When it's over, it goes to the line 2, and it goes successively until the end. I would like to find a way to execute the command ping at the same time in each line of the list. Is there a way to do it?
Thank you in advance!
Marcus Quintella
As Ari's suggested, googling ksh multithreading will produce a lot of ideas/solutions.
A simple example:
FILE_TMP="/temp.list"
while IFS= read line
do
ping $line &
done < "$FILE_TMP"
The trailing '&' says to kick the ping command off in the background, allowing loop processing to continue while the ping command is running in the background.
'course, this is just the tip of the proverbial iceberg as you now need to consider:
multiple ping commands are going to be dumping output to stdout (ie, you're going to get a mish-mash of ping output in your console), so you'll need to give some thought as to what to do with multiple streams of output (eg, redirect to a common file? redirect to separate files?)
you need to have some idea as to how you want to go about managing and (possibly) terminating commands running in the background [ see jobs, ps, fg, bg, kill ]
if running in a shell script you'll likely find yourself wanting to suspend the main shell script processing until all background jobs have completed [ see wait ]

Not able to establish Oracle SQL session from within a BASH script

#!/bin/bash
#Oracle DB Info for NEXT
HOST="1.2.3.4"
PORT="5678"
SERVICE="MYDB"
DB_USER=$(whoami)
DB_PASS=$(base64 -d ~/.passwd)
DB_SCHEMA="my_db"
#Section for all of our functions.
function SQLConnection(){
sqlplus "$DB_USER"/"$DB_PASS"#"$HOST":"$PORT"/"$SERVICE"
}
function Connected(){
SQLConnection <<EOF
select sys_context('USERENV','SERVER_HOST') from dual;
EOF
}
function GetJMS(){
SQLConnection <<EOF
set echo on timing on lines 200 pages 100
select pd.destination from ${DB_SCHEMA}.pd_notification pd where pd.org_id = '$ORGID';
EOF
}
TODAY=$(date +"%A %B %d, %Y")
read -r -p $'\n\nWhat is the ORG ID? ' ORGID
read -r -p $'\n\nWhat is the REMOTE QUEUE MANAGER NAME? ' RQM
read -r -p $'\n\nWhat is the IP address of the REMOTE QUEUE MANAGER? ' CONN
read -r -p $'\n\nWhat is the PORT of the REMOTE QUEUE MANAGER? ' PORT
echo -en "* $(whoami)\n* $TODAY\n* MQ Setup $ORGID\n\nDEFINE +\n\tCHANNEL('$RQM.LQML') +\n\tCHLTYPE(SDR) +\n\tCONNAME('$CONN($PORT)') +\n\tXMITQ('BUF.2.$ORGID.XMQ')\n\tCHAUTH(TLS_RSA_WITH_AES_256_CBC_SHA256)\n\nDEFINE +\n\tCHANNEL('LQML.$RQM') +\n\tCHLTYPE(RCVR) +\n\tTRPTYPE(TCP)\n\nDEFINE +\n\tQLOCAL('$RQM') +\n\tTRIGDATA('LQML.$RQM') +\n\tINITQ('SYSTEM.CHANNEL.INITQ') +\n\tTRIGGER USAGE(XMITQ)\n\n" > ~/mqsetup.mqsc
CONNECTED=$(Connected | awk 'NR==16')
echo -en "\n\nHello From: $CONNECTED\n\n"
for JMSDESTINATION in $(GetJMS | awk 'NR>=16&&NR<=24{print $1}')
do
read -r -p $'\n\nWhich REMOTE QUEUE NAME matches with this ${JMSDESTINATION}?' RNAME
QDESC=$(echo "$JMSDESTINATION" | tr '.' ' ' | tr '[[:upper:]]' '[[:lower:]]')
echo -en "\n\nDEFINE +\n\tQR($JMSDESTINATION) +\n\t\tREPLACE DESCR('$ORGID $QDESC Queue') +\n\t\tREPLACE MAXDEPTH(5000) +\n\t\tXMITQ('BUF.2.$ORGID.XMQ') +\n\t\tRNAME('$RNAME') +\n\t\tRQMNAME('$RQM')" >> ~/mqsetup.mqsc
done
Here is the script I've built, hoping to automate the setup of IBM MQ Queues and Channels. My problem is that outside this script, I can establish an SQL Session without an issue, directly from the shell, provided I input the variables seen in the script. I can call the functions and everything returns just as I'd hope it would. When I run the exact same things from within the script, I get timeout errors ... the "Hello From" is blank, which tells me there is no DB connection.
I'm totally stumped as to why it all works great from outside the script, but inside it times out.
I appreciate the eyes and the help!
You're overwritng a variable value. You have this at the top of the script:
PORT="5678"
but then later on you do:
read -r -p $'\n\nWhat is the PORT of the REMOTE QUEUE MANAGER? ' PORT
which overwrites your 5678 value with whatever is entered there. That port may not be listening on the DB server at all, or may be doing something else, or if you don't enter a value it'll default to port 1521 when you connect. But either way the connection is going to fail, either quickly or slowly depending on the port state (e.g. slower maybe if a firewall blocks it).
If you test the connection by adding a Connected call before the read calls (as I initially did) then it seems to be working fine; but the connections after the reads don't work because port value it tries to connect to is now wrong.
Use a different name for the two variables, e.g. RQ_PORT for the second one - both in its read command and the subsequent creation of the ~/mqsetup.mqsc file.
You may also find it useful to add the -l flag to your SQL*Plus call so that if the connection fails for some reason it won't re-prompt for credentials, which in some circumstances can make the script appear to hang until you hit enter a few times.
Not directly relevant to the problem, but when automating anything like this I usually also use the -s flag to suppress the banners (which can vary between environments); and if you're only interested in capturing query output I'd usually set headings and/or pagination off, and feedback off, and generally set SQL*Plus up to generate as little noise as possible - it makes parsing out the interesting bits easier.

get return code from plink?

In a DOS batch script, I'm running a single command on a remote (also windows) computer using plink. Formerly, this command was only run on the local machine, and was relying on the return code to determine success. Is there a way to easily get this information back through plink?
That's not possible with plink. The current consensus is to have the remote script echo its exit code to a log file, then use pscp to transfer the log file to the local machine.
See http://fixunix.com/ssh/74235-errorlevel-capturing-plink.html.
with plink 0.66
C:\Code>echo Y | "C:\Program Files (x86)\PuTTY\plink.exe" bob#myserver exit 42
C:\Code>echo %ERRORLEVEL%
42
Also for #John Wiersba's concern about when a connection cannot be made, this appears to be fixed
C:\CodeMisc>echo Y | "C:\Program Files (x86)\PuTTY\plink.exe" bob#garbageservername exit 42
Unable to open connection:
Host does not exist
C:\Code>echo %ERRORLEVEL%
1
Also note the piping of echo Y ... this enables you to accept the server fingerprint automatically (a little dangerous to say the least ... but our login server is load balanced, so you are always getting different fingerprints :( )
However as #LeonBloy notes, plink still has some connection conditions which return a zero exit code. If you know your exit code range and you don't have a good way of communicating back to windows via a file. You could either +3 to the exit code (if you know the exit code will never == 253-255) or you could apply a bitwise OR (I'd suggest exit $(($?|128)) - in bash).
Or if you don't care about the exact exit code, you could return 2 for success, and zero for failure. Thus a non-two exit code would indicate failure. In bash this would be: echo $((($?==0) << 1)). This would be by far the most robust general purpose solution, but you should make sure your exit code is logged for debug-ability.

Nano hacks: most useful tiny programs you've coded or come across

It's the first great virtue of programmers. All of us have, at one time or another automated a task with a bit of throw-away code. Sometimes it takes a couple seconds tapping out a one-liner, sometimes we spend an exorbitant amount of time automating away a two-second task and then never use it again.
What tiny hack have you found useful enough to reuse? To make go so far as to make an alias for?
Note: before answering, please check to make sure it's not already on favourite command-line tricks using BASH or perl/ruby one-liner questions.
i found this on dotfiles.org just today. it's very simple, but clever. i felt stupid for not having thought of it myself.
###
### Handy Extract Program
###
extract () {
if [ -f $1 ] ; then
case $1 in
*.tar.bz2) tar xvjf $1 ;;
*.tar.gz) tar xvzf $1 ;;
*.bz2) bunzip2 $1 ;;
*.rar) unrar x $1 ;;
*.gz) gunzip $1 ;;
*.tar) tar xvf $1 ;;
*.tbz2) tar xvjf $1 ;;
*.tgz) tar xvzf $1 ;;
*.zip) unzip $1 ;;
*.Z) uncompress $1 ;;
*.7z) 7z x $1 ;;
*) echo "'$1' cannot be extracted via >extract<" ;;
esac
else
echo "'$1' is not a valid file"
fi
}
Here's a filter that puts commas in the middle of any large numbers in standard input.
$ cat ~/bin/comma
#!/usr/bin/perl -p
s/(\d{4,})/commify($1)/ge;
sub commify {
local $_ = shift;
1 while s/^([ -+]?\d+)(\d{3})/$1,$2/;
return $_;
}
I usually wind up using it for long output lists of big numbers, and I tire of counting decimal places. Now instead of seeing
-rw-r--r-- 1 alester alester 2244487404 Oct 6 15:38 listdetail.sql
I can run that as ls -l | comma and see
-rw-r--r-- 1 alester alester 2,244,487,404 Oct 6 15:38 listdetail.sql
This script saved my career!
Quite a few years ago, i was working remotely on a client database. I updated a shipment to change its status. But I forgot the where clause.
I'll never forget the feeling in the pit of my stomach when I saw (6834 rows affected). I basically spent the entire night going through event logs and figuring out the proper status on all those shipments. Crap!
So I wrote a script (originally in awk) that would start a transaction for any updates, and check the rows affected before committing. This prevented any surprises.
So now I never do updates from command line without going through a script like this. Here it is (now in Python):
import sys
import subprocess as sp
pgm = "isql"
if len(sys.argv) == 1:
print "Usage: \nsql sql-string [rows-affected]"
sys.exit()
sql_str = sys.argv[1].upper()
max_rows_affected = 3
if len(sys.argv) > 2:
max_rows_affected = int(sys.argv[2])
if sql_str.startswith("UPDATE"):
sql_str = "BEGIN TRANSACTION\\n" + sql_str
p1 = sp.Popen([pgm, sql_str],stdout=sp.PIPE,
shell=True)
(stdout, stderr) = p1.communicate()
print stdout
# example -> (33 rows affected)
affected = stdout.splitlines()[-1]
affected = affected.split()[0].lstrip('(')
num_affected = int(affected)
if num_affected > max_rows_affected:
print "WARNING! ", num_affected,"rows were affected, rolling back..."
sql_str = "ROLLBACK TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
sql_str = "COMMIT TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
ret_code = sp.call([pgm, sql_str], shell=True)
I use this script under assorted linuxes to check whether a directory copy between machines (or to CD/DVD) worked or whether copying (e.g. ext3 utf8 filenames -> fusebl
k) has mangled special characters in the filenames.
#!/bin/bash
## dsum Do checksums recursively over a directory.
## Typical usage: dsum <directory> > outfile
export LC_ALL=C # Optional - use sort order across different locales
if [ $# != 1 ]; then echo "Usage: ${0/*\//} <directory>" 1>&2; exit; fi
cd $1 1>&2 || exit
#findargs=-follow # Uncomment to follow symbolic links
find . $findargs -type f | sort | xargs -d'\n' cksum
Sorry, don't have the exact code handy, but I coded a regular expression for searching source code in VS.Net that allowed me to search anything not in comments. It came in very useful in a particular project I was working on, where people insisted that commenting out code was good practice, in case you wanted to go back and see what the code used to do.
I have two ruby scripts that I modify regularly to download all of various webcomics. Extremely handy! Note: They require wget, so probably linux. Note2: read these before you try them, they need a little bit of modification for each site.
Date based downloader:
#!/usr/bin/ruby -w
Day = 60 * 60 * 24
Fromat = "hjlsdahjsd/comics/st%Y%m%d.gif"
t = Time.local(2005, 2, 5)
MWF = [1,3,5]
until t == Time.local(2007, 7, 9)
if MWF.include? t.wday
`wget #{t.strftime(Fromat)}`
sleep 3
end
t += Day
end
Or you can use the number based one:
#!/usr/bin/ruby -w
Fromat = "http://fdsafdsa/comics/%08d.gif"
1.upto(986) do |i|
`wget #{sprintf(Fromat, i)}`
sleep 1
end
Instead of having to repeatedly open files in SQL Query Analyser and run them, I found the syntax needed to make a batch file, and could then run 100 at once. Oh the sweet sweet joy! I've used this ever since.
isqlw -S servername -d dbname -E -i F:\blah\whatever.sql -o F:\results.txt
This goes back to my COBOL days but I had two generic COBOL programs, one batch and one online (mainframe folks will know what these are). They were shells of a program that could take any set of parameters and/or files and be run, batch or executed in an IMS test region. I had them set up so that depending on the parameters I could access files, databases(DB2 or IMS DB) and or just manipulate working storage or whatever.
It was great because I could test that date function without guessing or test why there was truncation or why there was a database ABEND. The programs grew in size as time went on to include all sorts of tests and become a staple of the development group. Everyone knew where the code resided and included them in their unit testing as well. Those programs got so large (most of the code were commented out tests) and it was all contributed by people through the years. They saved so much time and settled so many disagreements!
I coded a Perl script to map dependencies, without going into an endless loop, For a legacy C program I inherited .... that also had a diamond dependency problem.
I wrote small program that e-mailed me when I received e-mails from friends, on an rarely used e-mail account.
I wrote another small program that sent me text messages if my home IP changes.
To name a few.
Years ago I built a suite of applications on a custom web application platform in PERL.
One cool feature was to convert SQL query strings into human readable sentences that described what the results were.
The code was relatively short but the end effect was nice.
I've got a little app that you run and it dumps a GUID into the clipboard. You can run it /noui or not. With UI, its a single button that drops a new GUID every time you click it. Without it drops a new one and then exits.
I mostly use it from within VS. I have it as an external app and mapped to a shortcut. I'm writing an app that relies heavily on xaml and guids, so I always find I need to paste a new guid into xaml...
Any time I write a clever list comprehension or use of map/reduce in python. There was one like this:
if reduce(lambda x, c: locks[x] and c, locknames, True):
print "Sub-threads terminated!"
The reason I remember that is that I came up with it myself, then saw the exact same code on somebody else's website. Now-adays it'd probably be done like:
if all(map(lambda z: locks[z], locknames)):
print "ya trik"
I've got 20 or 30 of these things lying around because once I coded up the framework for my standard console app in windows I can pretty much drop in any logic I want, so I got a lot of these little things that solve specific problems.
I guess the ones I'm using a lot right now is a console app that takes stdin and colorizes the output based on xml profiles that match regular expressions to colors. I use it for watching my log files from builds. The other one is a command line launcher so I don't pollute my PATH env var and it would exceed the limit on some systems anyway, namely win2k.
I'm constantly connecting to various linux servers from my own desktop throughout my workday, so I created a few aliases that will launch an xterm on those machines and set the title, background color, and other tweaks:
alias x="xterm" # local
alias xd="ssh -Xf me#development_host xterm -bg aliceblue -ls -sb -bc -geometry 100x30 -title Development"
alias xp="ssh -Xf me#production_host xterm -bg thistle1 ..."
I have a bunch of servers I frequently connect to, as well, but they're all on my local network. This Ruby script prints out the command to create aliases for any machine with ssh open:
#!/usr/bin/env ruby
require 'rubygems'
require 'dnssd'
handle = DNSSD.browse('_ssh._tcp') do |reply|
print "alias #{reply.name}='ssh #{reply.name}.#{reply.domain}';"
end
sleep 1
handle.stop
Use it like this in your .bash_profile:
eval `ruby ~/.alias_shares`