I want to replace word "blue" to "red" in all text files named as 1_classification.dat, 2_classification.dat and so on. I want to edit the same file so I tried this code but it does not work. Where am I going wrong?
@files=glob("*_classification.dat");
foreach my $file (@files)
{
open(IN,$file) or die $!;
<IN>;
while(<IN>)
{
$_='~s/blue/red/g';
print IN $file;
}
close(IN)
}
It can be done using a single line:
perl -pi.back -e 's/oldString/newString/g;' inputFileName
Pay attention that oldString
is processed as a Regular Expression.
In case the string contains any of {}[]()^$.|*+?
(The special characters for Regular Expression syntax) make sure to escape them unless you want it to be processed as a regular expression.
Escaping it is done by \
, so \[
.
$_='~s/blue/red/g';
Uh, what??
Just
s/blue/red/g;
or, if you insist on using a variable (which is not necessary when using $_, but I just want to show the right syntax):
$_ =~ s/blue/red/g;
None of the existing answers here has provided a complete example of how to do this from within a script (not a one-liner). Here is what I did:
rename($file, $file.'.bak');
open(IN, '<'.$file.'.bak') or die $!;
open(OUT, '>'.$file) or die $!;
while(<IN>)
{
$_ =~ s/blue/red/g;
print OUT $_;
}
close(IN);
close(OUT);
Source: Stackoverflow.com