Programming

==> OUTPUT:
1 cust_034_60       2
|__ file_1___|  |_file_2_|
3 cust_406_4        3
|__ file_1___|  |_file_2_|

cust_034_60       2
|___key___|   |_value_|

$2 in f2 {
  print $0, f2[$2]
  }'

f2[$1]=$2;

awk  '{if(NR==FNR){#now read file_2 into f2
       f2[$1]=$2} 
      else #now read in file_1, because NR!=FNR
      {
         if($2 in f2){print $0, f2[$2]}}
      }' file_2 file_1

NR == FNR {
  ... some code ...
  next                    # jump directly to the next input line
                          # so the actions in the following blocks
                          #  don't execute when NR == FNR
  }
... here we're sure NR != FNR ...

1
00:00:01,400 --> 00:00:10,300
In the air war of Vietnam, one day stands out among all the rest.
2
00:00:10,300 --> 00:00:21,666
May 10, 1972, the full fury of American air power is unleashed on North Vietnam.
3
00:00:22,600 --> 00:00:30,433
More Vietnamese MiGs are shot down on this day than on any other day of the war.

1
00:00:01,400 --> 00:00:10,300
在越戰空戰史上，有個特殊日子與眾不同。
2
00:00:10,300 --> 00:00:21,666
1972年5月10日，美國空中武力對北越釋出飽和之憤怒。
3
00:00:22,600 --> 00:00:30,433
更多的北越米格機在該天較任何其他日子被擊落。

awk > "SRT" '{if(NR==FNR && length($0)> 0)
{#now read file_E into f2
f2[FNR]=$0} 
 
else if(length($0)> 0)
{#now read in file_C, because NR!=FNR
{if(FNR==1){end=NR-1}}
{for (i=1; i <= end; i++)
if( $0==f2[i]){print $0; next}
}
# {printf "|%d| --> |%s|\n", FNR, f2[FNR]}
printf "%s\n",f2[FNR];
printf "%s\n\n",$0
}
}' file_E file_C #

1
00:00:01,400 --> 00:00:10,300
In the air war of Vietnam, one day stands out among all the rest.
在越戰空戰史上，有個特殊日子與眾不同。
2
00:00:10,300 --> 00:00:21,666
May 10, 1972, the full fury of American air power is unleashed on North Vietnam.
1972年5月10日，美國空中武力對北越釋出飽和之憤怒。
3
00:00:22,600 --> 00:00:30,433
More Vietnamese MiGs are shot down on this day than on any other day of the war.
更多的北越米格機在該天較任何其他日子被擊落。

awk 'FNR == 1 {
  sub(/^\xef\xbb\xbf/, x)
  }
/-->/ { 
  idx = $0 
  $0 in d && $0 = $0 RS d[$0]
  }
  NR == FNR {
    !/^[0-9]+$/ && d[idx] = $0
    next
    }
  1' file_E file_C