Leetcode:195. Tenth Line以及管道命令pipeline

195. Tenth Line

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Question

Total Accepted: 9416  Total Submissions: 29373  Difficulty: Easy

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

# Read from the file file.txt and output the tenth line to stdout.

#NR 表示记录数，在执行过程中对应于当前的行号

   awk 'NR==10' file.txt

   <p class="p1"><span class="s1">guest-wireless-207-151-058-020:company hongruzh$ cat -n main.java</span></p><p class="p1"><span class="s1">     1<span>	</span>package com.company;</span></p><p class="p1"><span class="s1">     2<span>	</span></span></p><p class="p1"><span class="s1">     3<span>	</span>public class Main {</span></p><p class="p1"><span class="s1">     4<span>	</span></span></p><p class="p1"><span class="s1">     5<span>	</span>    public static void main(String[] args) {</span></p><p class="p1"><span class="s1">     6<span>	</span>        int INF = Integer.MAX_VALUE;</span></p><p class="p1"><span class="s1">     7<span>	</span>        int[][] rooms={{INF,-1,0,INF},</span></p><p class="p1"><span class="s1">     8<span>	</span>                {INF,INF,INF,-1},</span></p><p class="p1"><span class="s1">     9<span>	</span>                {INF,-1,INF,-1},</span></p><p class="p1"><span class="s1">    10<span>	</span>                {0,-1,INF,INF}};</span></p><p class="p1"><span class="s1">    11<span>	</span>        Solution solu = new Solution();</span></p><p class="p1"><span class="s1">    12<span>	</span>        solu.wallsAndGates(rooms);</span></p><p class="p1"><span class="s1">    13<span>	</span><span>	</span>// write your code here</span></p><p class="p1"><span class="s1">    14<span>	</span>    }</span></p><p class="p1"><span class="s1">    15<span>	</span>}</span></p><p class="p1"><span class="s1">guest-wireless-207-151-058-020:company hongruzh$ cat -n main.java|sed -n '10p';</span></p><p class="p1"><span class="s1">    10<span>	</span>                {0,-1,INF,INF}};</span></p><p class="p1">其中管道命令pipeline '|' cat -n main.java中的stdout内容是作为 stdin的内容来处理</p><p class="p1">’10p‘  p表示打印 10p就是打印第10行  如果是’1，10p‘ 就是打印1到10行</p>