Perl: Loop through a file and substitute

Question

I simply wanna read in a logfile, do a search and replace, and then write out the changes to that same logfile.

What's the best practice way of doing this in Perl?

Browder

Answer 1

I normally code up a one liner for this:

perl -i -pe 's/some/thing/' log.file

See Here

Champ

But why can't I use backreferances? Like perl -pi -e "s/foo(.*)bar/bar$1foo/" tezt2 doesn't work.. – Browder

Your shell is probably corrupting the string. Try replacing your ""s with ''s so that the * doesn't get expanded. – Cephalic

While strict is usually pointless for oneliners, enabling warnings with -w will occasionally catch problems for you; you should do it habitually. – Valine

Answer 2

This is often done with a one-liner:

perl -pi.bak -e "s/find/replace/g" <file>

Note the -i.bak portion -- this creates a backup file with the extension .bak. If you want to play without a net you can do this to overwrite the existing file without a backup:

perl -pi -e "s/find/replace/g" <file>

Siple

Answer 3

or you can use sed (I know... you asked about perl):

sed -i 's/find/replace/g' <file>

Breebreech

The way sed handles regular expression rules are...different, than Perl's, to say the least. – Beeswing