Emacs achieves some of its famed versatility by having various editing modes in which it behaves slightly differently. The word mode may sound technical or complicated, but what it really means is that Emacs becomes sensitive to the task at hand.
Text mode and C mode are major modes. A buffer can be in only one major mode at a time; to exit a major mode, you have to enter another one.
Whenever you edit a file, Emacs attempts to put you into the correct major mode. If you edit a file that ends in .c, it puts you into C mode. If you edit a file that ends in .el, it puts you in LISP mode.
|Fundamental mode||The default mode; no special behavior|
|Text mode||For writing text|
|Mail mode||For writing mail messages|
|RMAIL mode||For reading and organizing mail|
|View mode||For viewing files but not editing|
|Shell mode||For running a UNIX shell within Emacs|
|Telnet mode||For logging in to remote systems|
|Outline mode||For writing outlines|
|Indented text mode||For indenting text automatically|
|Nroff mode||For formatting files for nroff|
|TeX mode||For formatting files for TeX|
|LaTeX mode||For formatting files for LaTeX|
|C mode||For writing C programs|
|C++ mode||For writing C++ programs|
|Java mode||For writing Java programs|
|FORTRAN mode||For writing FORTRAN programs|
|Emacs LISP mode||For writing Emacs LISP functions|
|LISP mode||For writing LISP programs|
|LISP interaction ...|