Okay, the find . -type f -exec perl -pi.bak -e 's/old/new/g' {} \; command finds all files under the current directory and passes them through the command perl -pi.bak -e 's/old/new/g' {} which the {} delimiter is replaced with the filename. This I feel is the easiest way to find all files within a given directory tree and pass them through the perl command for in-place modification. Yes it isn't a "pure-Perl" solution, but sometimes reinventing the wheel isn't the best approach to a problem. And that too, as always, TIMTOWTDI.
 
The -n and -p command line switches are similar, both creating a loop similar to this around the passed -e code:
 
#   -n switch execution
#
LINE: while (<>) {
    ....    # your command is executed here
}

[download]

 
The difference is that the -p causes an additional print statement to be incorporated into the loop which is important so that your modified code is printed back out to the file. For example:
 
#   -p switch execution
#
LINE: while (<>) {
    ....    # your command is executed here
    } continue {
        print;
    }
}

[download]

 
Assuming you have already made your backups, you can remove the -i.bak switch which would made a backup of modified files, moving then to name.bak.
 

 
Update : The Perl command line switches are well documented at perlman:perlrun with additional examples.
 

 
Ooohhh, Rob no beer function well without!

In reply to Re: Re: Re: Need one-liner to s///g in all sub-dirs by rob_au
in thread Need one-liner to s///g in all sub-dirs by dvergin

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