Question

how to replace a String inside a File using perl ?

perl -pi -e 's/Arun/Brun/g' *

this worked fine for me

but when i tried to change class/students/a to class1/students1/B it throws error how to solve this problem ..i tried adding back slash (\) before every (/) but it didn’t help

perl -pi -e 's/class/students/a/class1/students1/B/g' *

Answer 1

You are using / as regex delimiter.
There are / even in your pattern and replacement. You need to somehow ensure that these / should not be treated as delimiter.

You have two options:

1. Escape the / in your pattern and replacement as:

   perl -pi -e 's/class\/students\/a/class1\/students1\/B/g' *
   

2. Or use a different delimiter:

   perl -pi -e 's#class/students/a#class1/students1/B#g' *
   

Method 2 is preferred as it keeps your regex short and clean.