|
|
This section introduces commands and, more importantly, special characters that let you
Characters with special meanings in the shell language
Character | Function |
---|---|
? [ ] | The asterisk, question mark, and brackets allow you to specify filenames by pattern matching. |
& | The ampersand places commands in background mode, leaving your terminal free for other tasks. |
; | The semicolon separates multiple commands on one command line. |
\ | The backslash turns off the meaning of special characters such as ? [ ] & ; > < and |. |
' . . . ' | Single quotes turn off the delimiting meaning of a space and the special meaning of all special characters. |
" . . . " | Double quotes turn off the delimiting meaning of a space and the special meaning of all special characters except $ and `. |
> | The greater than sign redirects the output of a command into a file (replacing the existing contents). |
< | The less than sign redirects the input for a command to come from a file. |
>> | Two greater than signs redirect the output of a command to be added to the end of an existing file. |
| | The vertical bar, or pipe, makes the output of one command the input of another command. |
` . . . ` | A pair of grave accents around a command embedded on a command line makes the output of the embedded command an argument on the larger command line. |
$ | The dollar sign retrieves the value of positional parameters and user-defined variables. It is also the default shell prompt. |