CentOSsed command to process text files

Cattest.txt 12341. Merge the upper and lower rows of sed & #39; $! N; s/\ n/\ t/&%39;test.txt 12342. merge matching mode and the next sed & #39;/2/{N; s/\ n/\ t/Jun 'test.txt 12343. merge all rows of sed & #39;: a; N; s/\ n //; ba; & #3

Cat test.txt

1
2
3
4
1. Merge the upper and lower rows
Sed '$! N; s/\ n/\ t/'test.txt

1 2
3 4
2. Merge matching mode and its next row
Sed '/2/{N; s/\ n/\ t/}' test.txt

1
2 3
4
3. Merge all rows
Sed ': a; N; s/\ n //; ba; 'test.txt

1 2 3 4

4. interactive parity rows
Sed '$! N; s/\ ([^ \ n] * \) \ n \ ([^ \ n] * \)/\ 2 \ n \ 1/'test.txt

2
1
4
3
6
5

5. delete empty rows
Sed '/^ $/d' test.txt

6. delete multiple empty rows.
Sed '/^ $/{N;/^ \ n * $/D}' test.txt

7. add blank lines after each row
# Cat test.txt | sed G
1

2

3

4

5

6

8. delete empty rows (that is, delete all even rows)
Sed 'n'; D'

9. multiple mkdir directories
DIR = 'SED ': a; N; s/\ n //; ba; 'test.txt'
Mkdir $ DIR
Create five directories, 1, 2, 3, 4, and 5 (the directory cannot be created using MPs queue)