bash 在两个不同的文件中显示重复的行

Display duplicate lines in two different files

提问by Chad D

I have two files and I would like to display the duplicate line. I tried this but it doesn't work :

我有两个文件，我想显示重复的行。我试过这个，但它不起作用：

cat id1.txt | while read id; do grep "$id" id2.txt; done

cat id1.txt | while read id; do grep "$id" id2.txt; done

I am wondering if there are any other way to display the duplicate lines in the file. Both of my 2 files contain list of ids. Thank you.

我想知道是否还有其他方法可以显示文件中的重复行。我的两个文件都包含 ID 列表。谢谢你。

回答by Jonathan Leffler

Are the files sorted? Can they be sorted?

文件排序了吗？它们可以排序吗？

If sorted:

如果排序：

comm -12 id1.txt id2.txt

If not sorted but using bash4.x:

如果未排序但使用bash4.x：

comm -12 <(sort id1.txt) <(sort id2.txt)

There are solutions using temporary files if you don't have bash4.x and 'process substitution'.

如果您没有bash4.x 和“进程替换”，则有使用临时文件的解决方案。

You could also use grep -F:

您还可以使用grep -F：

grep -F -f id1.txt id2.txt

This looks for the words in id1.txtthat appear in id2.txt. The only problem here is ensuring that an ID 1doesn't match every ID containing a 1somewhere. The -wor -xoptions available in some versions of grepwill work here.

这将查找id1.txt出现在 中的单词id2.txt。这里唯一的问题是确保 ID1不匹配每个包含1某处的ID 。某些版本中可用的-w或-x选项grep将在此处起作用。

回答by kamituel

If by detecting duplicates you mean printing lines which are the present in both files (or duplicate within one file), you can use uniq:

如果通过检测重复项，您的意思是打印两个文件中都存在的行（或在一个文件中重复），则可以使用uniq：

$ cat file1 file2 | sort | uniq -d

回答by Tuxdude

You could use the commcommand instead:

您可以改用以下comm命令：

sort id1.txt > id1.txt.sorted
sort id2.txt > id2.txt.sorted
comm -12 id1.txt.sorted id2.txt.sorted

If you want to do it in one command:

如果您想在一个命令中执行此操作：

comm -12 <(sort id1.txt) <(sort id2.txt)

Arguments to comm:

论据comm：

• The -1argument suppresses lines unique in the first file.
• The -2argument suppresses lines unique in the second file.
• If you pass a -3argument, it would suppress the common lines.

• 该-1参数禁止在第一个文件中唯一的行。
• 该-2参数禁止在第二个文件中唯一的行。
• 如果你传递一个-3参数，它会抑制公共行。