File Juicer
File Juicer for macOS
Overview of Formats

Search & Extract

Images

jpg jpeg 2000 gif png pdf wmf emf tiff eps pict bmp

Video

mov mpeg avi wmv

Sound

mp3 wav System 7 au aiff

Text

ascii rtf html

From:

avi cab cache chm dmg doc emlx exe ithmb m4p mht mp3 pdf pps ppt raw swf wps xls zip and other formats

CGI files from Web Servers

The CGI extension does not tell you much about the contents of the file, but rather that it has been generated by a web server. Usually it will be a HTML document which can be opened by all text editors, but it may be other file types as well.

Save as Web Archive

If the CGI file is HTML you can save it as a Web Archive with Safari and drop the archive on File Juicer to extract what is inside the archive.

You can drop CGI files on File Jucier to see if it contains any of the 20 formats File Jucier can extract.

Link

Wikipedia - about CGI