Quoting disables a character’s special meaning and allows it to be used literally, as itself. The following table displays characters that have special meaning to the Bash shell.
< > &
* ? [ ] ~ + - @ !
" ' \
Used in quoting other characters
Variable substitution (or command or arithmetic substitution)
space tab newline
These characters can be used for quoting:
Everything between " and " is taken literally, except for the following characters that keep their special meaning:
Variable (or command and arithmetic) substitution will occur.
Command substitution will occur.
This marks the end of the double quote.
Everything between ' and ' is taken literally except for another '. You cannot embed another ' within such a quoted string.
The character following a \ is taken literally. Use within " " to escape “, $, and '. Often used to escape itself, spaces, or newlines.
Just like " ", except that locale translation is done.
Similar to ' ', but the quoted text is processed for the following escape sequences.
Control character X
echo 'Single quotes "protect" double quotes'Single quotes "protect" double quotes $ ...