Are you trying to fix the Nagios error, Bad interpreter: No such file or directory ?

This guide is for you.

Bad interpreter: No such file or directory error in Nagios happens in the process of 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 Ibmi Media, as part of our Server Management Services, We regularly help our Customers to resolve such Nagios related issues.

How to fix Nagios error, 'bad interpreter no such file or directory' ?

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

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