Odd quirk with xargs and telnet Post: 302458127

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Top Forums UNIX for Dummies Questions & Answers Odd quirk with xargs and telnet Post 302458127 by treesloth on Wednesday 29th of September 2010 07:49:01 PM

09-29-2010

Registered User

Odd quirk with xargs and telnet

For a variety of strange reasons, I've set up an arrangement by which a server responds with "Hi there" if I connect on a specified port. This is a typical transaction:

Code:

# telnet example.com 3334
Trying 123.456.789.101...
Connected to example.com.
Escape character is '^]'.
Hi there
Connection closed by foreign host.

Now, I'm trying to use a quick and dirty way to do this concurrently, using xarg's -P (or max-procs, in some cases) option. Once this works, I'll increase the seq value, add -P concurrency, and be happy. The problem, though, is that I can't get the server's response to show up. Here's a trivial case:

Code:

# seq 1 | xargs -I DISCARD telnet example.com 3334
Trying 123.456.789.101...
Connected to example.com.
Escape character is '^]'.
Connection closed by foreign host.

So, the "1" should be discarded, as there is no DISCARD string in the command called by xargs, and the telnet command should be run. But, this trivial case should be the same thing as just running the telnet command alone since it's wrapped up in a negligible xargs. But, for some reason, the server's "Hi there" doesn't appear. Any idea why that is? I've tried redirecting stderr to stdout on the chance that it's some oddity in the way xargs handles errors, but no luck. I've also placed the telnet command into a little one-liner script and called that instead, without changing the output. Any suggestions? I've scratched my head many times. It didn't help... Many thanks in advance.

Last edited by treesloth; 09-29-2010 at 09:18 PM..

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LEARN ABOUT DEBIAN

xine-remote

XINE-REMOTE(1)						      General Commands Manual						    XINE-REMOTE(1)

NAME

       xine-remote - a small tool to connect xine remote control server.

SYNOPSIS

       xine-remote [options]

DESCRIPTION

       This manual page documents briefly the xine-remote tool.

       xine-remote  can  replace  a  raw  telnet  connection to a xine remote control server. It use the readline facilities (completion, vi/emacs
       shortcuts, command history, etc...).  By default, it try to connect the localhost, using the default port (see xine(1)).

OPTIONS

       The program follow the usual GNU command line syntax, with long ioptions starting with two dashes (`-').  A summary of options are included
       below.

       -H, --host <hostname>
	      Try to connect <hostname>.

       -P, --port <port>
	      Try to connect the host using <port>.

       -c, --command <command>
	      Send <command> to server then quit.  The command should be single quoted if it contain spaces or special characters.

       -n, --noconnect
	      Do not initiate the connection on startup.

       -v, --version
	      Display version.

       -h, --help
	      Display options summary.

COMMANDS

       Few commands are available, which are used to open or close a connection:

       ?      Display available commands (the xine-remote ones + server ones when connection is established).

       help <command>
	      Display the purpose of <command>, if that is omitted, display available commands.

       syntax <command>
	      Display the usage of <command>.

       version
	      Display version.

       open <server[:port]>
	      Open connection to server. A port can be optionally specified, using colon (:) separator.

       close  Close connection.

       quit   Leaving xine-remote.

SEE ALSO

       xine(1).

AUTHOR

       This manual page was written by Daniel Caujolle-Bert <f1rmb@users.sourceforge.net> for the xine project.

The xine project						    2002-04-16							    XINE-REMOTE(1)