File Types in linux

.bz2 — a file compressed with bzip2

.gz — a file compressed with gzip

.tar — a file archived with tar (short for tape archive), also known as a tar file

.tbz — a tarred and bzipped file

.tgz — a tarred and gzipped file.

.zip — a file compressed with ZIP compression, commonly found in MS-DOS applications. Most compressed files for Linux use the gzip compression, so finding a .zip archive for Linux files is rare.

For information on working with bzip2, gzip, and tar files, refer to Section 14.3 File Compression and Archiving.

File Formats
.au — an audio file

.gif — a GIF image file

.html/.htm — an HTML file

.jpg — a JPEG image file

.pdf — an electronic image of a document; PDF stands for Portable Document Format

.png — a PNG image file (short for Portable Network Graphic)

.ps — a PostScript file; formatted for printing

.txt — a plain ASCII text file

.wav — an audio file

.xpm — an image file

System Files
.conf — a configuration file. Configuration files sometimes use the .cfg extension, as well.

.lock — a lock file; determines whether a program or device is in use

.rpm — a Red Hat Package Manager file used to install software

Programming and Scripting Files
.c — a C program language source code file

.cpp — a C++ program language source code file

.h — a C or C++ program language header file

.o — a program object file

.pl — a Perl script

.py — a Python script

.so — a library file

.sh — a shell script

.tcl — a TCL script