Are you looking for a solution to ‘bad interpreter no such file or directory’ error in Nagios? We can help you with fixing it.

Generally, this issue occurs while creating scripts in the Windows environment and then porting them over to run on a Unix environment. This happens as the file is in a “Windows” format instead of a “Unix” format.

Here at Bobcares, we have seen several such Nagios-related issues as part of our Server Management Services for web hosts and online service providers.

Today we’ll take a look at how to fix this error message.

How we fix the ‘bad interpreter no such file or directory’ error in Nagios

Now let’s take a look at how our Support Engineers resolve this error message to our customers.

Since this issue occurs while creating scripts in Windows environment and then porting them over to run on a Unix environment. Here the file is in a “Windows” format instead of a “Unix” format.

So in order to resolve this problem, we shall convert the file to a Unix format. For that, we execute the following steps from an SSH session as a user with root privileges.

First, we install the required packages.

RHEL|CentOS
yum install -y dos2unix

Debian|Ubuntu
apt-get install -y dos2unix

Next, we convert the file to a Unix format:

dos2unix /usr/local/nagios/libexec/check_apc_pdu_load.sh

This will provide the below output:

dos2unix: converting file /usr/local/nagios/libexec/check_apc_pdu_load.sh to UNIX format …

After completing these steps, the plugin should execute as intended.

Also, we can rewrite the script in a Unix environment using any text editor and test.

If we want to write a file on Windows and then port over, we make sure the editor is set to create files in UNIX format.

In notepad++ in the bottom right of the screen, it tells us the document format. By default, it will say Dos\Windows. In order to change it, we follow the below steps:

settings >> preferences >> new document/default directory tab >> select the format as unix and close >> create a new document

We can remove the spurious CR characters. We can do it with the following command:

sed -i -e ‘s/\r$//’ NAME-OF-FILE.sh

[Need any further assistance in fixing Nagios errors? – We are here to help you]

Conclusion

Today, we saw the solution our Support Engineers provide a solution this Nagios problem.