How to change log file extension in Codeigniter

You can change it by application/config/config.php. Please find below mention code and set your custom extension.

/*  |--------------------------------------------------------------------------  | Log File Extension  |--------------------------------------------------------------------------  |  | The default filename extension for log files. The default 'php' allows for  | protecting the log files via basic scripting, when they are to be stored  | under a publicly accessible directory.  |  | Note: Leaving it blank will default to 'php'.  | */$config['log_file_extension'] = '';

You can also generate logs depends on your requirement as describe below.

/*  |--------------------------------------------------------------------------  | Error Logging Threshold  |--------------------------------------------------------------------------  |  | You can enable error logging by setting a threshold over zero. The  | threshold determines what gets logged. Threshold options are:  |  | 0 = Disables logging, Error logging TURNED OFF  | 1 = Error Messages (including PHP errors)  | 2 = Debug Messages  | 3 = Informational Messages  | 4 = All Messages  |  | You can also pass an array with threshold levels to show individual error types  |  |     array(2) = Debug Messages, without Error Messages  |  | For a live site you'll usually only enable Errors (1) to be logged otherwise  | your log files will fill up very fast.  | */$config['log_threshold'] = 1;

Set custom directory to save your log files.

/*  |--------------------------------------------------------------------------  | Error Logging Directory Path  |--------------------------------------------------------------------------  |  | Leave this BLANK unless you would like to set something other than the default  | application/logs/ directory. Use a full server path with trailing slash.  | */$config['log_path'] = '';

This will be used to set the permissions to log files.

/*  |--------------------------------------------------------------------------  | Log File Permissions  |--------------------------------------------------------------------------  |  | The file system permissions to be applied on newly created log files.  |  | IMPORTANT: This MUST be an integer (no quotes) and you MUST use octal  |            integer notation (i.e. 0700, 0644, etc.) */$config['log_file_permissions'] = 0644;

This will be used to set date format for each log entry.

/*  |--------------------------------------------------------------------------  | Date Format for Logs  |--------------------------------------------------------------------------  |  | Each item that is logged has an associated date. You can use PHP date  | codes to set your own date formatting  | */$config['log_date_format'] = 'Y-m-d H:i:s';

I hope this will help you.

Open the file /application/config/config.php and search for $config['log_file_extension'].Fill the empty value with your favourite extension.

| The default filename extension for log files. The default 'php' allows for| protecting the log files via basic scripting, when they are to be stored| under a publicly accessible directory.|| Note: Leaving it blank will default to 'php'.