Redirects

Question 1

How can you add text to a file or overwrite an existing file?

Answer 1

echo “text” > /path/to/file

Question 2

How can you append text to an existing file?

Answer 2

echo “text”&raquo_space; /path/to/file

Question 3

What are the 3 standard redirects in Linux?

Answer 3

stdin (0) stdout (1) stderr (2)

Question 4

What is the input redirect symbol?

Answer 4

<

Question 5

Give an example of the input redirect action

Answer 5

wc < testfile (sending the testfile into the word count program - same as cat testfile | wc)

Question 6

How can you suppress error output from a command?

Answer 6

<command></command>

2> /dev/null

Question 8

Give an example of the tee command

Answer 8

echo “TESTING” | tee testfile (saves to file and displays “TESTING” on stdout - overwrites existing)

Question 9

How can you append to file using tee?

Answer 9

echo “TESTING” | tee -a testfile

Question 10

What is the | (pipe) used for?

Answer 10

To send the output of one command to the input of another command

Question 11

How do you redirect output and error to the same place?

Answer 11

2>&1

Question 12

What location can you redirect to to discard output?

Answer 12

/dev/null