How to find/replace and increment a matched number with sed/awk?

Question

Straight to the point, I\'m wondering how to use grep/find/sed/awk to match a certain string (that ends with a number) and increment that number by 1. The closest I\'ve come

Answer 1

This perl command will search all files in current directory (without traverse it, you will need File::Find module or similar for that more complex task) and will increment the number of a line that matches cache_version=. It uses the /e flag of the regular expression that evaluates the replacement part.

perl -i.bak -lpe 'BEGIN { sub inc { my ($num) = @_; ++$num } } s/(cache_version=)(\d+)/$1 . (inc($2))/eg' *

I tested it with file in current directory with following data:

hello
cache_version=3
bye

It backups original file (ls -1):

file
file.bak

And file now with:

hello
cache_version=4
bye

I hope it can be useful for what you are looking for.

---

UPDATE to use File::Find for traversing directories. It accepts * as argument but will discard them with those found with File::Find. The directory to begin the search is the current of execution of the script. It is hardcoded in the line find( \&wanted, "." ).

perl -MFile::Find -i.bak -lpe '

    BEGIN { 
        sub inc { 
            my ($num) = @_; 
            ++$num 
        }

        sub wanted {
            if ( -f && ! -l ) {  
                push @ARGV, $File::Find::name;
            }
        }

        @ARGV = ();
        find( \&wanted, "." );
    }

    s/(cache_version=)(\d+)/$1 . (inc($2))/eg

' *