如何：使用 bash 将命令输出与文本文件进行比较
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How to: compare command output to text file with bash
提问by jlconlin
I'm trying to compare the output of the command
我正在尝试比较命令的输出
`ls -l directory`
with a file that I've created using the same command. (I'm trying a poor man's way of making sure no files have been modified.)
使用我使用相同命令创建的文件。（我正在尝试一个穷人的方式来确保没有文件被修改。）
The trouble is, I don't know how to diffthe output of the lscommand with the file that I've created. I've tried the following and each time it doesn't work
问题是，我不知道如何使用我创建的文件diff输出ls命令。我尝试了以下方法，但每次都不起作用
diff file.ls <(ls -l directory)
ls -l directory | xargs diff file.ls
ls -l directory | diff file.ls
diff file.ls < `ls -l directory`
What is the magic command to compare the output of lsto a file that I've already saved?
将输出与ls我已经保存的文件进行比较的神奇命令是什么？
回答by jlconlin
The answer (for posterity) is to do the following
答案（对于后代）是执行以下操作
diff file.ls <(ls -l directory)
When I did this previously, the output was blank. I thought I had done it wrong; in actuality there was no difference between the contents of the directory and my file.
当我以前这样做时，输出是空白的。我以为我做错了；实际上，目录的内容和我的文件之间没有区别。
<\facepalm>
<\面掌>
回答by robert
diffis easiest when you compare files.
diff比较文件时最简单。
$ ls $DIR > original.ls
do some stuff
$ ls $DIR > new.ls
$ diff original.ls new.ls
