Saving output to files

Catching the output

Normally a command's output appears on screen. The > symbol redirects it into a file instead:

echo hello > greeting.txt

Nothing prints — the text went into greeting.txt. Read it back with cat greeting.txt.

The > symbol sends a command's output into a file instead of the screen

Replace vs add

> replaces the file's contents (or creates it if new).
>> appends — it adds to the end, keeping what was there:

echo line one > notes.txt
echo line two >> notes.txt

Use >> when you are building up a file, like a log.

Send the output of echo into a file with >. Write hello into greeting.txt, then cat it back.

>> adds a line instead of replacing. Write first into log.txt, then append second, then show the file.

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