Question

如何从文件中获取：

This is a line 2
There is 1 line
imagine 3 lines
two times two is 4
There is no number here

以下内容：

2, This is a line 2
1, There is 1 line
3, imagine 3 lines
4, two times two is 4

因此，从行中检索前缀，它可以在行与行之间变化。如何在bash和perl中完成此操作？大概是这样的：

s/\d+/$&, $`$&$'/

Answer 1

使用perl one-liner

perl -ne 'print "$1, $_" if /(\d+)/' filename

切换：

-n：为输入文件中的每个“行”创建一个while(<>){...}循环。
-e：告诉perl在命令行上执行代码。

Answer 2

sed -En 's/.*([0-9]+).*/\1, &/p' filename

Answer 3

从命令行使用bash：

$ while read -r line; do 
    [[ $line =~ [0-9]+ ]] && echo "${BASH_REMATCH[0]}, $line"; 
done < file
2, This is a line 2
1, There is 1 line
3, imagine 3 lines
4, two times two is 4

将行的子文本前置到同一行

3 个答案: