This userreturn file type is obsolete. Such system files are from old operating systems or discontinued software. They are no longer actively used. userreturn files recently appeared on some anti-virus testing sites. They were tested for viruses. The userreturn extension seems to be for some text file. But the associated program is unknown.
In Linux, file extensions carry little meaning. They only cue the user on expected file content. That cue could be wrong. Extensions are less significant for Linux systems than file content.
To get a file’s extension in C#, use the GetExtension method. Or use a regular expression to extract the part after the last dot. Both can return the extension.
Node.js provides extname() to return a file’s extension. It tracks the last dot in a path or filename. Additional methods like parse() and MIME types can also handle extensions.
PHP offers built-in functions to get extensions. Use pathinfo() and specify PATHINFO_EXTENSION. Or create a custom function. Both approaches reliably return the file extension.
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