From: Chris Packham <judge.packham@gmail.com>
Date: Wed, 05 Jan 2011 23:22:17 GMT
Subject: Re: [BUG?] "git submodule foreach" when command is ssh
Message-ID: <AANLkTikCUKbHUrvXjWVyzmrZMzUtgrLrCDr8wSeFVgsZ@mail.gmail.com>
In-Reply-To: <20110105230334.GB9774@sigill.intra.peff.net>

On Thu, Jan 6, 2011 at 12:03 PM, Jeff King <peff@peff.net> wrote:
> On Thu, Jan 06, 2011 at 11:50:58AM +1300, Chris Packham wrote:
>
>> Actually this might be a ssh/bash bug (feature?). There is different
>> behaviour between
>>
>>   find . -maxdepth 1 -type d -a ! -name '\.*' | while read; do echo
>> $REPLY && ssh localhost ls /; done
>>
>> and
>>
>>   find . -maxdepth 1 -type d -a ! -name '\.*' | while read; do echo
>> $REPLY && ls /; done
>
> Ssh will opportunistically eat data on stdin to send to the other side,
> even though the command on the other side ("ls" in this case) will never
> read it. Because of course ssh has no way of knowing that, and is trying
> to be an interactive terminal. So it ends up eating some random amount
> of the data you expected to go to the "read" call.
>
> You can use the "-n" option to suppress it. For example:
>
>  $ (echo foo; echo bar) |
>    while read line; do
>      echo local $line
>      ssh host "echo remote $line"
>    done
>
> produces:
>
>  local foo
>  remote foo
>
> but:
>
>  $ (echo foo; echo bar) |
>    while read line; do
>      echo local $line
>      ssh -n host "echo remote $line"
>    done
>
> produces:
>
>  local foo
>  remote foo
>  local bar
>  remote bar
>
> which is what you want.
>
> -Peff

Thanks that makes sense and adding -n to my ssh invocations solves the problem.