execute commands and store command output to variable

Question

This script reads the system IP from hosts.txt, login to system, checks the OS type, executes a set of commands and print the output.

The ssh portion works fine, however the error (No such File or Directory) is shown after displaying output for 'ls''.

It seems the command /opt/hyperic/agent-current/bin/hq-agent.sh is not getting executed on remote host. The intend is to execute commands 'cd /opt;ls and also capture the command output to STATUS on each remote systems mentioned in host.txt.

When I run manaully the command on the remote system, the below output is returned. Any help on what could be wrong here?

  ~]# /opt/hyperic/agent-current/bin/hq-agent.sh status | awk 'NR==1{print $3 $4}'

isrunning

script is as below

#!/bin/bash
 while read host; do
 if ssh -o StrictHostKeyChecking=no -n root@$host '[ "$(awk "/CentOS/{print}" /etc/*release)" ] '
   then
    echo "(centos)"
    ssh -o StrictHostKeyChecking=no -n root@$host 'cd /opt;ls'
    STATUS=`/opt/hyperic/agent-current/bin/hq-agent.sh status | awk 'NR==1{print $3 $4}'`
   if [ "$STATUS" == "isrunning" ]
   then
      echo "$HOST == PASS"
   else
      echo "$HOST == FAIL"
  fi
  else
    echo "(generic)"
  fi
  done < hosts.txt

Output of the script --

 [email protected]'s password:
   firstboot
  puppet
  ./hq-enhanced.sh: line 14: /opt/hyperic/agent-current/bin/hq-agent.sh: No such file or   directory
  == FAIL

Geoff Williams · Accepted Answer · 2014-03-20 10:02:48Z

1

Ahh... I see what is happening:

Key to the question is:

ssh -o StrictHostKeyChecking=no -n root@$host 'cd /opt;ls'
STATUS=`/opt/hyperic/agent-current/bin/hq-agent.sh status | awk 'NR==1{print $3 $4}'`

the ssh command runs immediately and returns control to the script - at this point your not logged in via ssh anymore and the line starting STATUS executes wherever your running your script from.

To capture the output of the ssh command you would need something like:

STATUS=`ssh root@foobar -c 'cd /foo/bar && /opt/hyperic/agent-current/bin/hq-agent.sh ...'`

HTH

answered Mar 20, 2014 at 10:02

Geoff Williams

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