使用文件2中与bash（可能是awk）匹配的密钥值将值更新到文件_1中

我有以下情况： 包含ddl的文件_1可以是这样的：

column_A  varchar(50)
column_B  int
column_C  varchar (100)

文件_2包含文件_1中更改的内容，例如

column_B  varchar(50)

我想将文件_1从“column_B int”更改为“column_B varchar（50）” 当然，我还需要所有其他线路保持不变

使用awk，我成功地识别了更改的线路

awk 'NR==FNR{a[$1]++;next} ($1 in a)' file_1 file_2

但我不知道如何将其写入文件_1

---

我该如何实现它呢？

请您尝试以下内容，并用GNU

awk

中显示的示例编写和测试

awk 'FNR==NR{a[$1]=$2;next} ($1 in a){$2=a[$1]} 1' file_2 file_1

若上面的命令正在终端上为您打印正确的结果，那个么您可以使用下面的命令将输出保存到输入文件中

awk 'NR==FNR{a[$1]++;next} ($1 in a)' file_1 file_2 > temp && mv temp file_1

说明：添加上述内容的详细说明

awk '               ##Starting awk program from here.
FNR==NR{            ##Checking condition if FNR==NR which will be true when first Input_file named file_2 is being read.
  a[$1]=$2          ##Creating array a with index of $1 and its value is $2 from current line.
  next              ##next will skip all further statements from here.
}
($1 in a){          ##Checking condition if first field is present in array a then do following.
  $2=a[$1]          ##Assigning array a value with index of first field to 2nd field.
}
1                   ##1 will print current line here.
' file_2 file_1     ##Mentioning Input_file names here.

---

请您尝试使用GNU

awk

中显示的样本编写并测试以下内容

awk 'FNR==NR{a[$1]=$2;next} ($1 in a){$2=a[$1]} 1' file_2 file_1

若上面的命令正在终端上为您打印正确的结果，那个么您可以使用下面的命令将输出保存到输入文件中

awk 'NR==FNR{a[$1]++;next} ($1 in a)' file_1 file_2 > temp && mv temp file_1

说明：添加上述内容的详细说明

awk '               ##Starting awk program from here.
FNR==NR{            ##Checking condition if FNR==NR which will be true when first Input_file named file_2 is being read.
  a[$1]=$2          ##Creating array a with index of $1 and its value is $2 from current line.
  next              ##next will skip all further statements from here.
}
($1 in a){          ##Checking condition if first field is present in array a then do following.
  $2=a[$1]          ##Assigning array a value with index of first field to 2nd field.
}
1                   ##1 will print current line here.
' file_2 file_1     ##Mentioning Input_file names here.