perl regex warning: \1 better written as $1 at (eval 1) line 1
use strict;
use warnings;
my $newPasswd = 'abc123';
my @lines = ( "pwd = abc", "pwd=abc", "password=def", "name= Mike" );
my %passwordMap = (
'pwd(\\s*)=.*' => 'pwd\\1= $newPasswd',
'password(\\s*)=.*' => 'password\\1= $newPasswd',
);
print "@lines\n";
foreach my $li开发者_运维问答ne (@lines) {
while ( my ( $key, $value ) = each(%passwordMap) ) {
if ( $line =~ /$key/ ) {
my $cmdStr = "\$line =~ s/$key/$value/";
print "$cmdStr\n";
eval($cmdStr);
last;
}
}
}
print "@lines";
run it will give me the correct results:
pwd = abc pwd=abc password=def name= Mike
$line =~ s/pwd(\s*)=.*/pwd\1= $newPasswd/
\1 better written as $1 at (eval 2) line 1 (#1)
$line =~ s/password(\s*)=.*/password\1= $newPasswd/
\1 better written as $1 at (eval 3) line 1 (#1)
pwd = abc123 pwd=abc password= abc123 name= Mike
I don't want to see the warnings, tried to use $1 instead of \1, but it does not work. What should I do? Thanks a lot.
\1
is a regex pattern that means "match what was captured by the first set of capturing parens." It makes absolutely no sense to use that in a replacement expression. To get the string captured by the first set of capturing parens, use $1
.
$line =~ s/pwd(\s*)=.*/pwd\1= $newPasswd/
should be
$line =~ s/pwd(\s*)=.*/pwd$1= $newPasswd/
so
'pwd(\\s*)=.*' => 'pwd\\1= $newPasswd',
'password(\\s*)=.*' => 'password\\1= $newPasswd',
should be
'pwd(\\s*)=.*' => 'pwd$1= $newPasswd',
'password(\\s*)=.*' => 'password$1= $newPasswd',
or better yet
qr/((?:pwd|password)\s*=).*/ => '$1= $newPasswd',
I see a lot of repetition in your code.
Assuming you're using Perl 5.10 or later, this is how I would have written your code.
use strict;
use warnings;
use 5.010;
my $new_pass = 'abc123';
my @lines = ( "pwd = abc", "pwd=abc", "password=def", "name= Mike" );
my @match = qw'pwd password';
my $match = '(?:'.join( '|', @match ).')';
say for @lines;
say '';
s/$match \s* = \K .* /$new_pass/x for @lines;
# which is essentially the same as:
# s/($match \s* =) .* /$1$new_pass/x for @lines;
say for @lines;
Assuming that the pattern of your pattern matching map stays the same, why not get rid of it and say simply:
$line =~ s/\s*=.*/=$newPassword/
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