删除多个以某个单词开头的文本文件中的行

Question

I have hundreds of text files in one directory. For all files, I want to delete all the lines that begin with HETATM. I would need a csh or bash code.

I would think you would use grep, but I'm not sure.

Answer 1

Use sed like this:

sed -i -e '/^HETATM/d' *.txt

to process all files in place.

-i means "in place".

-e means to execute the command that follows.

/^HETATM/ means "find lines starting with HETATM", and the following d means "delete".

Make a backup first!

If you really want to do it with grep , you could do this:

#!/bin/bash

for f in *.txt
do
   grep -v "^HETATM" "%f" > $$.tmp && mv $$.tmp "$f"
done

It makes a temporary file of the output from grep (in file $$.tmp ) and only overwrites your original file if the command executes successfully.

Answer 2

使用grep的-v选项获取所有不匹配的行：

grep -v '^HETATM' input.txt > output.txt