文件里怎么引用变量

hisongy

123.sql内容：select userid, msisdn, testertype, dst_testertype, oper_date from statuser.dw_to_up_result where oper_date = $GDATE

#!/usr/bin/perl
use strict;
use File::Basename;

my $GDATE=20160815;
my @fileContent;
my $fileString;

代码：
    open INFILE, "<123.sql" || die "can't open $123.sql  !";

    @fileContent = <INFILE>;
    chomp(@fileContent);
    $fileString = join " ",@fileContent;
    print "$fileString";


    #while(<INFILE>
    #{
    #    print "$_";
    #}
close INFILE;
输出结果 怎么才能引用$GDATE的值

stanley_tam

这样？

1. #!/usr/bin/perl
   
2. use strict;
   
3. use File::Basename;
   
4. 
   
5. my $GDATE=20160815;
   
6. my @fileContent;
   
7. my $fileString;
   
8. 
   
9. open INFILE, "<123.sql" || die "can't open $123.sql  !";
   
10. 
    
11. @fileContent = <INFILE>;
    
12. chomp(@fileContent);
    
13. $fileString = join " ",@fileContent;
    
14. 
    
15. my $string;
    
16. $fileString = qq{\$string = "$fileString"};
    
17. eval $fileString;
    
18. print $string;
    
19. 
    
20. close INFILE;
    
21. 
    
22. __END__

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sunzhiguolu

回复 2# stanley_tam
大师, 有个地方不明白 还请指点下:

#!/usr/bin/perl -w
use strict;

my $GDATE = '20160815';
while (<DATA>){
    my $line = qq ("$_");
    # eval $line;
}

__DATA__
select userid, msisdn, testertype, dst_testertype, oper_date from statuser.dw_to_up_result where oper_date = $GDATE

这种双层嵌套双引号的情况, 是个啥意思? 好像还必须是这样, 不然就不行! (知道您老人家厉害, 简单点解释就行, 谢谢)

   

stanley_tam

qq相当于双引号，后面的符号成对就可以了，用起来比下面这样方便。

1. $fileString = "\$string = \"$fileString\"";

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回复 3# sunzhiguolu


   

sunzhiguolu

回复 4# stanley_tam
\"$fileString\" 这个双引号的作用能解释下吗, 谢谢.

   

stanley_tam

加了引号变量$fileString的值如下，这样才是一个合法的perl语句。如果没有引号，会报语法错误的。

1. $string = "select userid, msisdn, testertype, dst_testertype, oper_date from statuser.dw_to_up_result where oper_date = $GDATE"

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回复 5# sunzhiguolu


   

RE_HASH

$>  cat 123.sql |perl -npe '$GDATE="2016-08-18"; s/\$(\w+)/${$1}/g;'