When issuing commands, you can specify where you want the standard input, output and errors to go, and to be able to do this you need to do a bit of redirection. A combination of the most useful redirections with corresponding file descriptors is shown in Table 5.1.
When using standard error in redirection, you must use a file descriptor, but for standard input and output this is optional. Table 5.1 shows both methods for completeness.
|Command > filename||Send standard output to a new filename|
|Command >> filename||Send standard output to filename (appended)|
|Command 1 > filename||Send standard output to filename|
|Command > filename 2>&1||Send all output (including errors) to filename ...|