Leetcode: Tenth Line

Get idea from here

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Question

How would you print just the 10th line of a file?

For example, assume that file.txt has the following content:

Line 1
Line 2
Line 3
Line 4
Line 5
Line 6
Line 7
Line 8
Line 9
Line 10
Your script should output the tenth line, which is:
Line 10
[show hint]

Hint:
1. If the file contains less than 10 lines, what should you output?
2. There’s at least three different solutions. Try to explore all possibilities.

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Solution

Mistakes are made

1. 
   
2. didn’t consider the situation that file contain less than 10 lines.
   

head -n 10 file.txt | tail -n 1
It is not right

Correct Solution

Solution 1 (sed)

sed -n '10p' file.txt

Solution 2(awk)

awk 'if(NR==10){print $0}' file.txt

Solution 3

tail -n+10 file.txt | head -n 1

tail -n

-n, –lines=K Output the last K lines, instead of the default of the last 10; alternatively, use “-n +K” to output lines starting with the Kth.

Keep in mind that -n+K, output lines starting with Kth

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take-home message

awk, sed, tail can all solve this problem. These three commands are able to deal with txt editor.