System Administration PT1

Question 1

What is the difference between vi and vim?

Answer 1

vim stands for ‘Vi IMproved’ and is an enhanced version of vi. It includes features like syntax highlighting, multiple undo levels, and plugin support, which vi lacks.

Question 2

How do you open a file in vi or vim?

Answer 2

Use vi filename or vim filename in the terminal.

Question 3

What are the modes in vi/vim?

Answer 3

1. Normal mode (for navigation/commands)
2. Insert mode (for editing text)
3. Command-line mode (for saving, quitting, etc.)

Question 4

How do you switch to Insert mode in vi/vim?

Answer 4

Press i (insert), a (append), or o (open a new line).

Question 5

How do you exit Insert mode in vi/vim?

Answer 5

Press Esc to return to Normal mode.

Question 6

How do you save and quit in vi/vim?

Answer 6

Press Esc, then type :wq and hit Enter.

Question 7

How do you quit without saving in vi/vim?

Answer 7

Press Esc, then type :q! and hit Enter.

Question 8

How do you search for text in vi/vim?

Answer 8

Press /, then type the search term and hit Enter.

Question 9

How do you delete a line in vi/vim?

Answer 9

In Normal mode, type dd.

Question 10

What does the sed command do?

Answer 10

sed is a stream editor that can perform text transformations on an input stream (a file or input from a pipeline).

Question 11

How do you use sed to replace ‘apple’ with ‘orange’ in a file?

Answer 11

sed 's/apple/orange/g' filename

Question 12

What does the g flag mean in sed?

Answer 12

It stands for ‘global’, meaning all occurrences in the line will be replaced.

Question 13

How do you edit a file in place using sed?

Answer 13

Use the -i flag, e.g., sed -i 's/old/new/g' filename

Question 14

How do you delete a specific line using sed?

Answer 14

sed '3d' filename deletes line 3.

Question 15

How do you copy a line in vi/vim?

Answer 15

In Normal mode, use yy to yank (copy) the current line.

Question 16

How do you paste a copied line in vi/vim?

Answer 16

Use p to paste after the cursor, or P to paste before.

Question 17

How do you undo and redo changes in vi/vim?

Answer 17

Use u to undo and Ctrl+r to redo.

Question 18

How do you move to the beginning and end of a line in vi/vim?

Answer 18

Use 0 to move to the beginning and $ to the end.

Question 19

How do you jump to a specific line number in vi/vim?

Answer 19

Use :linenumber, e.g., :20 to jump to line 20.

Question 20

How do you search and replace across the whole file in vi/vim?

Answer 20

Use :%s/old/new/g

Question 21

How do you record and replay a macro in vi/vim?

Answer 21

Use q<letter> to start recording, do actions, then press q to stop. Replay with @<letter>.

Question 22

How do you set line numbers in vim?

Answer 22

In command mode, use :set number.

Question 23

How do you turn off line numbers in vim?

Answer 23

Use :set nonumber.

Question 24

What does :syntax on do in vim?

Answer 24

Enables syntax highlighting.

Question 25

What is the difference between `:wq` and `ZZ` in vim?

Answer 25

Both save and quit, but `ZZ` doesn't require pressing `:`.

Question 26

How do you print only lines that match a pattern using `sed`?

Answer 26

`sed -n '/pattern/p' filename`

Question 27

How do you delete all blank lines using `sed`?

Answer 27

`sed '/^$/d' filename`

Question 28

How do you replace only the first occurrence in a line with `sed`?

Answer 28

`sed 's/old/new/' filename` (no `g` flag)

Question 29

How do you use sed to edit multiple patterns?

Answer 29

`sed -e 's/one/1/g' -e 's/two/2/g' filename`

Question 30

How do you save sed output to a new file?

Answer 30

`sed 's/old/new/g' filename > newfile.txt`

Question 31

Can `sed` use regular expressions?

Answer 31

Yes, `sed` supports basic and extended regex patterns.

Question 32

How do you replace a string that includes slashes in `sed`?

Answer 32

Use a different delimiter like `#`: `sed 's#/old/path/#/new/path/#g'`