Question

在我的文件中，我有像

这样的行

String sql="select * from "+
             "emp_data";

我想替换它像

String sql = Query1;

我怎样才能使用perl

我正在使用

$curUrl ="select * from emp_data" ;
$curUrl = quotemeta $curUrl;
$newVariable = "Query1";
$data =~ s/$curUrl/$newVariable/g;

这是为单线工作。不是为了破碎的

Answer 1

尝试进行两次替换。

$curUrl ="select * from emp_data" ;
$curUrl = quotemeta $curUrl;
$newVariable = "Query1";
$data = 'String sql="select * from "+
         "emp_data";';

$data=~s/"|\+|\n\s+//g;  # Here i replace the " + and \n\s character with empty.

$data =~s/$curUrl/$newVariable/g;
print $data;

Answer 2

您可以考虑使用此经过测试的sed脚本：

sed -n '
:1
/^.*[+][ ]*$/ {
  h;
  :2
  n; H; /^.*[+][ ]*$/ {
    b2
  }
  x 
  s/[+\n\t\r]//g
  s/["][[:space:][:blank:]]*["]//g
  s/["][[:space:][:blank:]]*select [*] from emp_data[[:space:][:blank:]]*["]/Query1/
   p; x;
   b1;
}'

测试：

sed -n '
:1
/^.*[+][ ]*$/ {
  h;
  :2
  n; H; /^.*[+][ ]*$/ {
    b2
  }
  x 
  s/[+\n\t\r]//g
  s/["][[:space:][:blank:]]*["]//g
  s/["][[:space:][:blank:]]*select [*] from emp_data[[:space:][:blank:]]*["]/Query1/
   p; x;
   b1;
}' myfile.txt

String sql=Query1;

Answer 3

use strict;
use warnings; 
use 5.020;
use autodie;
use Data::Dumper;

# Here, the variables $/, $^I, and @ARGV either have their default values
# or some other values that were set by code appearing here.

{
    local $/ = ";";   #local => temporarily change the value of this variable until the closing parenthesis of this block is encountered
    local $^I = ".bak";
    local @ARGV = 'data.txt';

    while (<>) {
        my $perl_statement = $_;
        $perl_statement =~ s/sql = .*/sql = Query1/xms ;
        print $perl_statement;  #This is redirected into the file.
    }
}  #Automatically restores the previous values for $/, $^I, and @ARGV.

$/ =＆gt;输入行分隔符（默认=＆gt;“\ n”）。使<$INFILE>读取并包括指定为一行的字符 $^I =＆gt;如果设置为字符串（默认=＆gt; undef），则使菱形运算符神奇，这样您就可以在某处编辑文件。任何打印语句都将写入新文件，其名称将与原始文件相同。如果您编写$^I = ".bak"，则原始文件将存储在原始文件名加“.bak”扩展名的文件中。空白字符串表示没有备份 @ARGV =＆gt;钻石操作员从该数组中的文件中读取。

示例运行：

~/pperl_programs$ cat data.txt
String sql="select * from "+
             "emp_data";
hello word="select * from "+
             "emp_data";

~/pperl_programs$ perl 1.pl 

~/pperl_programs$ cat data.txt
String sql = Query1
hello word="select * from "+
             "emp_data";

或者，也许您想要替换所有出现的模式：

use strict;
use warnings; 
use 5.020;
use autodie;
use Data::Dumper;

my $pattern = q{"select * from "+
             "emp_data"};

{
    local $/ = ";"; 
    local $^I = "";
    local @ARGV = 'data.txt';

    while (<>) {
        my $perl_statement = $_;
        $perl_statement =~ s/= \Q$pattern/ = Query1/xms;
        print $perl_statement;
    }
}

示例运行：

~/pperl_programs$ cat data.txt
String sql="select * from "+
             "emp_data";
hello word="select * from "+
             "emp_data";

~/pperl_programs$ perl 1.pl 

~/pperl_programs$ cat data.txt 
String sql = Query1;
hello word = Query1;

使用Perl从文件替换多行字符串

3 个答案: