195 Tenth line

问题描述

Given a text file file.txt, print just the 10th line of the file.

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
Note:

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.

解决方案

1. 使用head 和 tail

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

2. 使用sed

sed '10p' file.txt

3. 使用awk

awk 'NR==10' file.txt

4. 使用脚本

no=0                                                              
while IFS= read -r line                                          
do  
    ((no=$no+1))
    if [[ $no -eq 10 ]]                                             
    then                                                        
        echo $line
	break
    fi                                                      
done < "file.txt"