将包含字符串的行复制到shell脚本中的另一个文件

Question

I am new to shell scripting and I am trying to figure out the following.

How to search a file for a line containing a particular string and copy that line to a new file if the line is present?

Answer 1

grep "string" file >copyFile

This would create a new file or empty an existing file.

grep "string" file >>copyFile

This would create a new file or append found string to an existing file.

Nota: "string" is a regex . Take a look at man grep for syntax.