Common file extensions in Linux

I hope my friends who want to learn Linux can use it a bit. The following is the beginning:
. Bz2 ------ compressed Bzip2 File
. GZ ------ compressed GZIP file
. Tar ------ tar package file (package file is not compressed file)
. TBZ ------ package tar and compress the file with bzip
. Tgz ----- files packaged with tar and compressed with Gzip
. Au ----- audio file
. Gif ----- GIF Image File
. Html/. htm ----- HTML file
. Jpg ----- JPEG Image File
. Pdf ------ electronic document (in PDF format)
. PNG ----- PNG Image File
. PS ------ postscinpt file (print format file)
. Txt ------ plain text file
. Wav ----- audio file
. XPM ----- Image File
. Conf ------- configuration file
. Lock ------- lock file (used to determine whether a file or device is used)
. RPM ------ redhatpackage. Manager file (package or package)
. C ------- C sourceProgramCodeFile
. Cpp ------ C ++ source code file
. H ------- header file of C or C ++ Program
. O ------ program target file

. Pl ------ Perl script file
. So ----- class library file