excerpt from ls man page

Example for .bashrc:
export LSCOLORS="exfxcxdxbxegedabagacad"

a     black
b     red
c     green
d     brown
e     blue
f     magenta
g     cyan
h     light grey
A     bold black, usually shows up as dark grey
B     bold red
C     bold green
D     bold brown, usually shows up as yellow
E     bold blue
F     bold magenta
G     bold cyan
H     bold light grey; looks like bright white
x     default foreground or background

Note that the above are standard ANSI colors.  The actual display may differ depending on the color capabilities of the terminal in
use.

The order of the attributes are as follows:

1.   directory
2.   symbolic link
3.   socket
4.   pipe
5.   executable
6.   block special
7.   character special
8.   executable with setuid bit set
9.   executable with setgid bit set
10.  directory writable to others, with sticky bit
11.  directory writable to others, without sticky bit

The default is "exfxcxdxbxegedabagacad", i.e. blue foreground and default background for regular directories, black foreground and red
background for setuid executables, etc.