re-write a string with text and numbers onto a newline and insert text

Question

In Short, I want to split single line output string into multiple rows and label each raw with the hostname.

Hostname ProcessName CPUCore

output=$(ssh -q -o "StrictHostKeyChecking yes" $ssh_host 'ps -eo comm,lastcpu | grep rrcp')

How to insert loop through a return out put that looks like.

rrcpd 17 rrcpd 0

and re-write as

Hostname1 rrcpd 17
Hostname1 rrcpd 0

Note

• The numbers can very from 0-32

• Hostname is a variable string $myhost

• The text does change, meaning it is not strictly rrcpd, it could be e.g.

  rrcpd 17 rrcpd 0

  Cheese 3 cakes 8

  Cats 9 dogs 3

Command that run on each host

output=$(ssh -q -o "StrictHostKeyChecking yes" $ssh_host 'ps -eo comm,lastcpu | grep rrcp')

The output can come back with 3-5 process when I remove the grep, hence I want to be able to split each output and add the hostname to the raw to label each output. I am checking what processes are running on each host.

rrcpd 0 rrcp_mon.sh 24

rrcpd 0

rrcpd 0

rrcpd 0 rrcpd 1

rrcpd 0 rrcpd 0 rrcp_mon 24 rrcp_mon 24

rrcpd 0

rrcpd 0

rrcpd 17 rrcpd 0

ard 9 ssh 32 httpd 21 bax 22

I have modified the provided below and managed to get it to work

#!/bin/bash
for remote in $(cat ssh_hosts2.txt)
do
    ssh -q -o StrictHostKeyChecking=yes "$remote" ps -eo comm,lastcpu |
    sed "s/^/$remote /"
done

Answer 1

please try this,

I have saved the given sample output in file /tmp/test.txt.

 xargs -n 2 | sed 's/^/Hostname1 /' 

• -n means maximum arguments per line.

For example;

cat /tmp/test.txt  | xargs -n 2 | sed 's/^/Hostname1 /g' 
Hostname1 rrcpd 17
Hostname1 rrcpd 0
Hostname1 Cheese 3
Hostname1 cakes 8
Hostname1 Cats 9
Hostname1 dogs 3

Answer 2

The only reason you would see the type of data that you show (more than two fields per line in the output of the ssh command) is when you collect the output of your ssh+ps call into a variable and then output it without quoting it properly, as in output=$(ssh ...) followed by echo $output instead of echo "$output". Luckily, you don't need to collect the data in a variable at all.

while read remote; do
    ssh -n -q -o StrictHostKeyChecking=yes "$remote" ps -eo comm,lastcpu |
    awk -v host="$remote" '/rrcp/ { print host, $1, $2 }'
done <hosts.txt

Here, awk is reading directly from the ssh command and also does the work originally done by grep in your code. It assumes that it will get lines with two fields and will prefix each pair of fields with the given hostname (read from hosts.txt).

Alternatively,

while read remote; do
    ssh -n -q -o StrictHostKeyChecking=yes "$remote" ps -eo comm,lastcpu |
    sed "s/^/$remote /"
done <hosts.txt

Here, we simply prefix each line with the hostname read from the text file.