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16.9 Redirecting Standard Input 241

Now let’schecktheﬁle by typing:

cat sneakers.txt

And there it is – with the contents of home.txt at the end.

What we were saying when we typed that command was, “append the output from the ﬁle home.txt

to the ﬁle sneakers.txt.”

By appending the output, we’ve saved ourselves a step or two (and a bit of disk clutter) by using

existing ﬁles, rather than creating a new ﬁle.

Compare the results of the ﬁles sneakers.txt and saturday now, and you’ll see that they’re

identical. To make your comparison, just type:

cat sneakers.txt; cat saturday

The contents of both ﬁles will be displayed - ﬁrst sneakers.txt,thensaturday (as shown in

Figure 16.14).

Tip: Remember that when you append output, you’ve got to include the double greater-

than symbols (>>). Otherwise, you’ll end up replacing the very ﬁle to which you want

to append information!

(By the way, if you’re curious about the use of the semi-colon in that last command, read on. We’ll

cover that later in this chapter.)

Summary: To append output, use two greater-than symbols (>>). For example: cat

addthisfile >> tothisfile.

16.9 Redirecting Standard Input

Not only can you redirect standard output, you can perform the same type of redirection with stan-

dard input.

Here’showitworks:

When you use the redirect standard input symbol <,you’re telling the shell that you want a ﬁle to be

read as input for a command.

We can use a ﬁle we’ve already created to demonstrate this idea. Just type:

1 2 ... 248 249 250 251 252 253 254 255 256 257 258 ... 299 300

Brak uwag

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