bash while loop with ssh only last output displays

Question

I have server list in file and in a while loop I will read and runt he command using ssh. it displays only last server uptime output. other servers its not displaying.

eg:

cat a
host1
host2

cat a | while read s; do ssh -q $s -x "uptime"; done

it shows only host2 uptime output.

we changed to run like this it displays both servers output

cat a | while read s; do echo "ssh -q $s -x uptime"|bash; done

I like to understand, why we need while read loop displaying only last output.

Is anyother way we can execute the ssh remote command using while loop?

Thanks SR

`ssh` is eating your standard input. Use the `-n` flag to prevent that. — Etan Reisner, Mar 06 '15 at 15:46
possible duplicate of [ssh breaks out of while-loop in bash](http://stackoverflow.com/questions/9393038/ssh-breaks-out-of-while-loop-in-bash) — Etan Reisner, Mar 06 '15 at 15:47
ssh with -n works, also redirecting stdin to /dev/null works — sfgroups, Mar 06 '15 at 16:11

score 0 · Accepted Answer · answered Mar 06 '15 at 15:43

0

You should do it like this:

while read -r s
 do ssh -q $s -x "uptime" </dev/null
done < a

This is happening because ssh is trying to read from stdin

answered Mar 06 '15 at 15:43

arco444

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bash while loop with ssh only last output displays

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