Command Shell Symbols and Execution

Common Shell Symbols


ENTER                      : Execute a Command Line.
;                                  : Separate commands on the same command line.
‘command‘                 : Execute a command.
$(command)               : Execute a command.
[]                                 : Match on a class of possible characters in filenames.
\                                  : Quote the following character. Used to quote special characters.
|                                   : Pipe the standard output of one command as input for another command.
&                        : Execute a command in the background.
!                                  : History command.


File Expansion Symbols


*              : Match on any set of characters in filenames.
?              : Match on any single character in filenames.
[]             : Match on a class of characters in filenames.


Redirection Symbols:


>              : Redirect the standard output to a file or device, creating the file if it does not exist and overwriting the file if it does exist.
>!             : Force the overwriting of a file if it already exists. This overrides the noclobber option.


<               : Redirect the standard input from a file or device to a program.


>>             : Redirect the standard output to a file or device, appending the output to the end of the file.



Standard Error Redirection Symbols:


2> : Redirect the standard error to a file or device.
2>>  : Redirect and append the standard error to a file or device.
2>&1  : Redirect the standard error to the standard output.


>&  : Redirect the standard error to a file or device.
|&   : Pipe the standard error as input to another command.