[SOLVED] CentOS 7 -eq: unary operator expected

Issue

I have to check Tomcat 8 is running or not. For this I am using the below script.

#!/bin/bash

statuscode=$(wget --server-response http://localhost:8080 2>&1 | awk '/^  HTTP/{print $2}')

if [ $statuscode -eq 200 ]
then
    echo "TOMCAT OK"
    exit 0
else
    echo "TOMCAT CRITICAL"
    exit 2
fi

When I run this script on CentOS 7.

If Tomcat 8 is running then script is running without any error.

If Tomcat 8 is stopped then script is running with following error

line 5: [: -eq: unary operator expected

How can I fix this issue?

Solution

Check if the variable is not empty before comparing it against the expected output.

#!/bin/bash

statuscode=$(wget --server-response http://localhost:8080 2>&1 | awk '/^  HTTP/{print $2}')

if [ -n "$statuscode" ] && [ $statuscode -eq 200 ]
then
    echo "TOMCAT OK"
    exit 0
else
    echo "TOMCAT CRITICAL"
    exit 2
fi

Answered By - Thirupathi Thangavel