我有一个包含以下数据的文件:
wednesday
Weekday
thursday
Weekday
friday
Weekday
saturday
MaybeNot
sunday
MaybeNot
monday
Weekday
tuesday
Weekday
我想$:$
在每个备用行前面插入一个字符串,以便将文件重写如下:
wednesday
$:$Weekday
thursday
$:$Weekday
friday
$:$Weekday
saturday
$:$MaybeNot
sunday
$:$MaybeNot
monday
$:$Weekday
tuesday
$:$Weekday
我将如何使用 awk/sed 实现这一目标?