Grep

Question 1

Why would you use grep?

Answer 1

Grep is available on all computers with Unix/Linux, while Ack and Ag are not always available.

Question 2

What is the basic usage of grep?

Answer 2

grep

Question 3

By default, grep uses ______ to search for patterns in a file.

Answer 3

regular expressions

Question 4

How can we count the number of times a pattern is found in a file?

Answer 4

with the -c flag

grep -c ruby README.md

Question 5

How can we display line numbers in the output of a grep search?

Answer 5

grep -n Ruby README.md

Question 6

How can we perform a case-insensitive search with grep?

Answer 6

the -i flag

Question 7

How can you use grep to search through multiple files?

Answer 7

Simply include all of the files you want to search within the command
grep rails README.md RELASING_RAILS.rdoc

Question 8

What flag do we need to search through a directory?

Answer 8

The recursive flag (-R)

grep -R “Read” .

Question 9

Which flag can we use to narrow the search to file names within the directory with certain parameters?

Answer 9

grep -R –include=”*.yml” “Read” .

Question 10

How would you write grep -R –include=”*.yml” “Read” . in Ag?

Answer 10

ag Read -G yml$

Question 11

How can we search for lines in a file that don’t contain the letter a?

Answer 11

Using the invert search flag (-v)

grep -v “a” README.md