awk - 在文件中查找以下部分重复的行

Question

使用 shell 命令，打印包含前一行的文件的任何行。

示例文件：

i love potatoes
i love shoes
i love super shoes
i love shoe
i love shoes

命令必须打印：“i love shoes”因为它是唯一包含前一行内容的行（因为“i love shoes”包含“i love shoe”）

任何想法 ？

标签： awkgrep

Answer 1

输入：

$ cat input
i love potatoes
i love shoes
i love super shoes
i love apple
i love apples
i eat melon
i eat melons
i eat apples and i eat melons

命令：

awk '{if(NR>1 && length(previous)>0 && index($0,previous)>0){print};previous=$0;}' input

输出：

i love apples
i eat melons
i eat apples and i eat melons

说明：

{
  #skip the first line as by definition there is no line before it
  #if the previous line is not empty and if the current line contains the previous line 
  # (e.g. you can find an index >0 of the previous line string in the current line), 
  #print the current line
  if (NR>1 && length(previous) > 0 && index($0, previous) > 0) { 
     print $0
  }
  #assign the current line to previous line and continue the processing
  previous = $0
}