While true loop stopped Post: 303027755

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Top Forums Shell Programming and Scripting While true loop stopped Post 303027755 by bakunin on Sunday 23rd of December 2018 08:57:05 AM

12-23-2018

Registered User

Quote:

Originally Posted by sadique.manzar

My script condition on connection refused have break command.

To be honest i fail to see a justification for the break reserved word here. The purpose of break is to get out of loops like this:

Code:

while <condition> ; do
     something
     if <other-condition> ; then
          break
     fi
done

Which will cause the while .. do....done to be left when "other-condition" is met. Still, break (as well as its companion continue) should be used with extreme care or rather be avoided in most cases. They both are in fact thinly veiled GOTOs and there is a reason why structured programming languages without GOTOs were invented - it simply makes the task of keeping up with understanding (your own) code and the program flow a lot easier.

So, let us take a step back: what are you trying to achieve? State a clear and complete problem and we sure can work out a solution which does not depend on break or similar constructs.

Another possibility is: ssh allocates a terminal and therefore captures <stdin> - as does while. Alas, what one usually experiences is not that it fails permanently but a rather inconsistent behavior of "sometimes it works, sometimes not". Might it be that this is the case here?

I hope this helps.

bakunin

PS: on second thoughts, you should also get rid of the echos and the backticks - both are antiquated, deprecated and not best practice for quite some long time now.

bakunin

bakunin

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LEARN ABOUT DEBIAN

ssh-argv0

SSH-ARGV0(1)						    BSD General Commands Manual 					      SSH-ARGV0(1)

NAME

     ssh-argv0 -- replaces the old ssh command-name as hostname handling

SYNOPSIS

     hostname | user@hostname [-l login_name] [command]

     hostname | user@hostname [-afgknqstvxACNTX1246] [-b bind_address] [-c cipher_spec] [-e escape_char] [-i identity_file] [-l login_name]
     [-m mac_spec] [-o option] [-p port] [-F configfile] [-L port:host:hostport] [-R port:host:hostport] [-D port] [command]

DESCRIPTION

     ssh-argv0 replaces the old ssh command-name as hostname handling.	If you link to this script with a hostname then executing the link is
     equivalent to having executed ssh with that hostname as an argument.  All other arguments are passed to ssh and will be processed normally.

OPTIONS

     See ssh(1).

FILES

     See ssh(1).

AUTHORS

     OpenSSH is a derivative of the original and free ssh 1.2.12 release by Tatu Ylonen.  Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
     Theo de Raadt and Dug Song removed many bugs, re-added newer features and created OpenSSH.  Markus Friedl contributed the support for SSH
     protocol versions 1.5 and 2.0.  Jonathan Amery wrote this ssh-argv0 script and the associated documentation.

SEE ALSO

     ssh(1)

Debian Project							 September 7, 2001						    Debian Project

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