Hello all.
Here the description of the issue I am having.
I am writing a bash test script which reads lines from a file, builds ISO messages, sends them to a server,
reads the response with response code and reports the result of the test to a file or on the screen.

The message that I need to send is 94 characters long.
Here's the portion of a code that I initially wrote:

###############################################

#~ Open socket.
exec 3<>/dev/tcp/172.26.0.25/9991

#~ Send msg.
echo "$msg_out" >&3 # OK but adds EOL character which confuses the server.


#~ Receive msg.
read -r msg_in <&3
echo "msg_in: $msg_in"

###############################################

It works OK with the "echoserver".
However, it does not on a real server.
The symptom is that the program is blocked on "read" statement.
One of the facts that is confirmed by server people is that the message received by a server is actually 95 bytes long.

So, based on this information I have 2 questions:

1. Is there any other way to do what I do in line "echo "$msg_out" >&3" to avoid End Of Line character?
2. Am I using the correct way to read from socket? "read -r msg_in <&3".

Thanks for your help,
vouser.

Never tried using your method of using sockets in a shell script. When confronted by such tasks, I typically turn to netcat (nc, on most installations). Perhaps your newline is coming from the echo command, and can be supressed with the -n switch.
--- rod.

1. Use printf(1), not echo.
2. Use the -u argument to read.

Rod:
thanks a lot for your post.
It took care of my question #1.
With "-n" switch the server people confirmed that they get exactly 94 bytes.
I still have a problem reading from the server, which is my question #2.
What's interesting is that with "-n" switch even "echoserver" can't read the msg back (it could before).
Looks like I need a better way to read.
Thanks again,
vouser.

You need -n for read as well, otherwise it waits for a newline.

just in case anybody was wondering, i ended up using dd:

with $1 beeing the amount of bytes to read. this wont block while reading the result.

the complete script can be found here: http://blog.chris007.de/?p=238