DQ - BASH

Question 1

Listing the non-hidden contents of the current directory without any options

Answer 1

ls

Question 2

Listing the non-hidden contents of path /home/dq

Answer 2

ls /home/dq

Question 3

Listing the non-hidden contents of the current directory in long format

Answer 3

ls -l

Question 4

Listing all contents of the current directory

Answer 4

ls -a

Question 5

Listing all contents of /home/dq in long format, except for the directories . and ..

Answer 5

ls -Al

Question 6

Change to directory /filename

Answer 6

cd /filename

Question 7

Change to the parent directory of the current directory

Answer 7

cd ..

Question 8

Change to the parent directory of the parent directory of the current directory

Answer 8

cd ../..

Question 9

Change to your home directory

Answer 9

cd

       OR

cd ~

Question 10

Change to the home directory of user dq

Answer 10

cd ~dq

Question 11

Change to the previous directory

Answer 11

cd -

Question 12

Creating a directory called my_dir

Answer 12

mkdir my_dir

Question 13

Deleting an empty directory called my_dir

Answer 13

rmdir my_dir

Question 14

Interactively creating a copy of file my_file1 as my_file2

Answer 14

cp -i my_file1 my_file2

Question 15

Create a copy of directory my_dir1 as my_dir2

Answer 15

cp -R my_dir1 my_dir2

Question 16

Deleting file my_file

Answer 16

rm my_file

Question 17

Deleting the non-empty directory my_dir

Answer 17

rm -R my_dir

Question 18

Moving my_file to my_dir

Answer 18

mv my_file my_dir

Question 19

Renaming my_file as our_file

Answer 19

mv my_file our_file

Question 20

Wildcard to match any single character

Answer 20

?

Question 21

Wildcard to match any multitude of string characters

Answer 21

*

Question 22

Wildcard to match k,3, z, or J

Answer 22

[k3zJ]

Question 23

Wildcard matching any character NOT in k,3, z, or J

Answer 23

[!k3zJ]

Question 24

Wildcard for letters (case insensitive)

Answer 24

[[:alpha:]]

Question 25

Wildcard for numbers

Answer 25

[[:digit:]]

Question 26

Wildcard for letters or numbers

Answer 26

[[:alnum:]]

Question 27

Wildcard for lowercase letter

Answer 27

[[:lower:]]

Question 28

Wildcard for uppercase letter

Answer 28

[[:upper:]]

Question 29

All files whose name is three characters long

Answer 29

???

Question 30

All files ending with .tsv

Answer 30

*.tsv

Question 31

All files starting with the first 2 decades of this century, followed by an underscore

Answer 31

20[01][[:digit:]]_*

Question 32

All files starting with either a lowercase letter or zero, followed by a question mark and ending in .txt

Answer 32

[[:lower:]0]\?*.txt

Question 33

Identify current user

Answer 33

whoami

Question 34

Identify user id, group id, and groups for a user

Answer 34

id

Question 35

Identify all groups for a user

Answer 35

group

Question 36

See file's metadata

Answer 36

stat file

Question 37

Adding execution permission to the owner on file

Answer 37

chmod u+x file

Question 38

Removing writing permission to the primary group on file

Answer 38

chmod g-w file

Question 39

Setting read and execution permissions to others on file

Answer 39

chmod o=rx file

Question 40

Add write permissions to owner, remove execute from primary group, and set others to read only

Answer 40

chmod u+w,g-x,o=r file

Question 41

Octal notation for permissions

Answer 41

R W X | 4 2 1

Question 42

Changing both the ownership and the group of file1 to new_owner and new_group

Answer 42

sudo chown new_owner:new_group file1

Question 43

Changing the ownership of file while maintaining its group

Answer 43

sudo chown new_owner file

Question 44

Changing the group of file while maintaining its ownership

Answer 44

sudo chown :new_group file

Question 45

Run a command with superuser privileges

Answer 45

sudo command

Question 46

Identify the type of a command

Answer 46

type command

Question 47

Create an alias for the "date" command as d

Answer 47

alias d=date

Question 48

Remove the alias named d

Answer 48

unalias d

Question 49

Get a brief description of what an executable file does

Answer 49

whatis command

Question 50

Access the manual of an executable file

Answer 50

man command

Question 51

Access the manual of a built-in command

Answer 51

help command

Question 52

See the contents of a file with less

Answer 52

less filename

Question 53

See the contents of a file with less without wrapipng lines

Answer 53

less -S filename

Question 54

What are the five different types of commands?

Answer 54

``` file builtin alias function keyword ``` (Only the executable files and built-ins have documentation)

Question 55

Seeing the first 15 rows of filename

Answer 55

head -n 15 filename

Question 56

Seeing the last 15 rows of filename

Answer 56

tail -n 15 filename

Question 57

Counting number of lines, words, and characters in filename

Answer 57

wc filename

Question 58

Pretty printing a CSV file:

Answer 58

column -s"," -t filename

Question 59

Extract a random sample of five rows from filename

Answer 59

shuf -n 5 filename

Question 60

Determining the type of filename

Answer 60

type filename

Question 61

Concatenate files together

Answer 61

cat file1 file2

Question 62

Concatenate files together in revers order will preserving line order

Answer 62

tac file1 file2

Question 63

Concatenate csv files together and then sort by the following in order: Column 1 lexicographical order ascending Column 3 numerical order descending Columns 5 through 7 as one field

Answer 63

sort -t"," -k1,1 -k3,3gr -k5-7 file1 file2

Question 64

Remove duplicate lines from a file

Answer 64

sort -u filename

Question 65

Selecting columns 2 , 3 and 7 through 9 on filename with : as a separator

Answer 65

cut -d":" -f2,3,7-9

Question 66

Print the lines of a file that does not match a regex pastern. Include the line number and make the search case-insensitive, and exclude the filename prefix

Answer 66

grep -vnih 'RegEx_Patern' filename

Question 67

See all the lines of a file except for the first row

Answer 67

tail -n+2

Question 68

Simply pring to screen "Hello, world!"

Answer 68

echo "Hello, world!"

Question 69

Create empty files

Answer 69

touch file1 file2

Question 70

Overwrite a file by redirecting the output of a command

Answer 70

cmd >filename

Question 71

Append a file with the output of a command

Answer 71

cmd >>filename

Question 72

Pipe the output of a command to the input of another command

Answer 72

cmd1 | cmd2

Question 73

Discard the output of a command

Answer 73

cmd >/dev/null

Question 74

Redirect stdout to a file

Answer 74

cmd >filename --OR-- cmd 1>filename

Question 75

Redirecting stdout and stderr to out and err respectively

Answer 75

cmd >out 2>err

Question 76

Redirecting stdout and stderr to all_output

Answer 76

cmd >all_output 2>&1

Question 77

Redirecting stdin from the shell to a file named input_file

Answer 77

cmd