在 Linux 上连接两个文件

我有两个文件；我想加入他们。

$cat t1
 1 1.2
 2 2.2
$cat t2
 1
 2
 1

我想要下面的输出

$cat joind.txt
 1 1.2
 2 2.2
 1 1.2

但是当我使用join命令，第三行不会出现在输出中。

一个简单的awk就足够了：

awk 'FNR==NR{a[$1]=$2;next} {print $1, a[$1]}' t1 t2
1 1.2
2 2.2
1 1.2

Breakup:

NR == FNR {                  # While processing the first file
  a[$1] = $2                 # store the second field by the first
  next                       # move to next record in 1st file
}
{                            # while processing the second file
  print $1, a[$1]            # print $1 and the remembered
                             # value from the first file.
}