Unix in a Nutshell, 4th Edition

Quoting

Quoting disables a character’s special meaning and allows it to be used literally, as itself. The characters in the following table have special meaning to tcsh .

Characters	Description
;	Command separator
&	Background execution
()	Command grouping
|	Pipe
* ? [ ] ~ ^	Filename metacharacters
{ }	String expansion characters (usually don’t require quoting )
< > & !	Redirection symbols
! ^	History substitution, quick substitution
" ' \	Used in quoting other characters
'	Command substitution
$	Variable substitution
space tab newline	Word separators

The characters that follow can be used for quoting:

" "

Everything between " and " is taken literally except for the following characters, which keep their special meaning:

$

Variable substitution will occur.

'

Command substitution will occur.

"

The end of the double quote.

\

Escape next character.

!

The history character.

newline

The newline character.

' '

Everything between ' and ' is taken literally except for ! (history), another ', and newline.

\

The character following a \ is taken literally. Use within " " to escape ", $, ', and newline. Use within ' ' to escape newlines. Often used to escape itself, spaces, or newlines. Always needed to escape a history character (usually !).

Examples

    % echo 'Single quotes "protect" double quotes'
    Single quotes "protect" double quotes

    % echo "Don't double quotes protect single quotes too?"
    Don't double quotes protect single quotes too?

    %