Perl搜索并替换不起作用

Question

I am trying to replace a string in a file but my procedure seems to be removing the string and not replacing it with what I want

Example

perl -ne 'print unless s/ServerIp=${Solid.host}/ads/;' needsToBeReplaced.prp > blah.txt

will remove

"ServerIp=${Solid.host}" and just leave the line blank instead of printing "ads" in its place

I am running in Windows by the way. Also I have no 3rd parameter in the regex because I only want to change the first occurrence. I have also tried

perl -pi -e 's/ServerPort=${Solid.port}/ads/;' needsToBeReplaced.txt 

but I get permission errors so editing in place is a no go

Answer 1

You print the line only if the substitution is not successful. If you want to print always, do not use unless :

perl -pe "s/ServerIp=\${Solid.host}/ads/;" needsToBeReplaced.prp > blah.txt

You should also escape the dollar sign to prevent its interpretation by Perl.

Also note that double quotes must be used on MS Windows.

Answer 2

With what you've got now, if the substitute succeeds, it will return a true value, which means unless will be true, which means nothing will be printed. You could do it like this:

perl -ne 's/ServerIp=${Solid.host}/ads/; print;' needsToBeReplaced.prp > blah.txt