The following environment variables affect the execution of ls (and ls-F):

     BLOCKSIZE	     If the environment variable BLOCKSIZE is set, the block
		     counts (see -s) will be displayed in units of that size block.

     CLICOLOR	     Use ANSI color sequences to distinguish file types.  See
		     LSCOLORS below.  In addition to the file types mentioned
		     in the -F option some extra attributes (setuid bit set,
		     etc.) are also displayed.	The colorization is dependent
		     on a terminal type with the proper termcap(5) capabili-
		     ties.  The default ``cons25'' console has the proper
		     capabilities, but to display the colors in an xterm(1),
		     for example, the TERM variable must be set to
		     ``xterm-color''.  Other terminal types may require simi-
		     lar adjustments.  Colorization is silently disabled if
		     the output isn't directed to a terminal unless the
		     CLICOLOR_FORCE variable is defined.

     CLICOLOR_FORCE  Color sequences are normally disabled if the output isn't
		     directed to a terminal.  This can be overridden by set-
		     ting this flag.  The TERM variable still needs to refer-
		     ence a color capable terminal however otherwise it is not
		     possible to determine which color sequences to use.

     COLUMNS	     If this variable contains a string representing a decimal
		     integer, it is used as the column position width for dis-
		     playing multiple-text-column output.  The ls utility cal-
		     culates how many pathname text columns to display based
		     on the width provided.  (See -C and -x.)

     LANG	     The locale to use when determining the order of day and
		     month in the long -l format output.  See environ(7) for
		     more information.

     LISTLINKS	     If the `listlinks' shell variable is set,  ls-F will identify symbolic links
	       in more detail (only on systems that have them, of course):

	       @   Symbolic link to a non-directory
	       >   Symbolic link to a directory
	       &   Symbolic link to nowhere

	       listlinks also slows down ls-F and causes partitions holding files
	       pointed to by symbolic links to be mounted.

     LISTFLAGS	     If  the	`listflags' shell variable is set to `x', `a' or `A', or
	       any combination thereof (e.g., `xA'), they are used as flags to ls-F,
	       making it act like `ls -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA').
	       On machines where `ls -C'  is  not the default, ls-F acts like `ls -CF', 
	       unless listflags contains an `x', in which case it acts like `ls -xF'.  

	       ls-F  passes  its arguments  to  ls(1)  if it is given any switches,
	       so `alias ls  ls-F' generally does the right thing.
	     
	       The ls-F builtin can list files using different colors  depend-
	       ing  on the filetype or extension.  See the color tcsh variable
	       and the LSCOLORS environment variable (below).

     LSCOLORS	     The value of this variable describes what color to use
		     for which attribute when colors are enabled with
		     CLICOLOR.	This string is a concatenation of pairs of the
		     format fb, where f is the foreground color and b is the
		     background color.

		     The color designators are as follows:

			   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 fore-
		     ground and default background for regular directories,
		     black foreground and red background for setuid executa-
		     bles, etc.

     LS_COLWIDTHS    If this variable is set, it is considered to be a colon-
		     delimited list of minimum column widths.  Unreasonable
		     and insufficient widths are ignored (thus zero signifies
		     a dynamically sized column).  Not all columns have
		     changeable widths.	 The fields are, in order: inode,
		     block count, number of links, user name, group name,
		     flags, file size, file name.

     TERM	     The CLICOLOR functionality depends on a terminal type
		     with color capabilities.

     TZ		     The timezone to use when displaying dates.	 See
		     environ(7) for more information.