如何在 AWK 中填充 CSV 中的空单元格？

Question

我有一个像这样的 CSV 文件，@作为分隔符：

Chapter 1@This is some text.
        @This is some more text.
        @This is yet some more text.
Chapter 2@This is some text.
        @This is some more text.
        @This is yet some more text.

第一列包含章节编号。第二列包含该章的文本。

我需要填写 A 列中的所有章节编号，以便下面的任何空单元格都填充章节编号。例如，输出将是这样的：

Chapter 1@This is some text.
Chapter 1@This is some more text.
Chapter 1@This is yet some more text.
Chapter 2@This is some text.
Chapter 2@This is some more text.
Chapter 2@This is yet some more text.

如何填写表格 A 列中的所有空单元格？

Answer 1

你可以这样使用awk：

awk  'BEGIN{FS=OFS="@"} {if ($1 ~ /^[ \t]*$/) $1=ch; else ch=$1} 1' file

Chapter 1@This is some text.
Chapter 1@This is some more text.
Chapter 1@This is yet some more text.
Chapter 2@This is some text.
Chapter 2@This is some more text.
Chapter 2@This is yet some more text.

使用简单的正则表达式检查，我们验证是否$1为非空，然后我们设置变量 ch as name of the first chapter. Then in next subsequent lines we set chapter name to the value we've stored in variablech`。