Perl: Find Replace String Pairs in Directory

By Xah Lee. Date: . Last updated:

Here is a Perl program that does find and replace. I've been using it from 2000 to 2005. (switched to Python in ~2005, then switched to elisp for all my text processing needs in ~2007. See: Emacs Lisp Tutorial.)

In this Perl version, there are several features. It can do regex pattern, do backup to a separate folder, exclude huge files, count number of replacements.

#!/usr/local/bin/perl

=pod

 Description:
This script does find and replace on a given foler recursively.

 Features:
* multiple Find and Replace string pairs can be given.
* The find/replace strings can be set to regex or literal.
* Files can be filtered according to file name suffix matching or other 
criterions.
* Backup copies of original files will be made at a user specified 
folder that preserves all folder structures of original folder.
* A report will be generated that indicates which files has been 
changed, how many changes, and total number of files changed.
* files will retain their own/group/permissions settings.

usage:
1. edit the parts under the section '#-- arguments --'.
2. edit the subroutine fileFilterQ to set which file will be checked or 
skipped.

to do:
* in the report, print the strings that are changed, possibly with 
surrounding lines.
* allow just find without replace.
* add the GNU syntax for unix command prompt.
* Report if backup directory exists already, or provide toggle to 
overwrite, or some other smarties.

Date created: 2000/02
Author: Xah Lee, XahLee.org

=cut

#-- modules --

use strict;
use File::Find;
use File::Path;
use File::Copy;
use Data::Dumper;

#-- arguments --

# the folder to be search on.
my $folderPath = q[/Users/xah/web/UnixResource_dir/xx];

# this is the backup folder path.
my $backupFolderPath = q[/Users/xah/xxxb];

my %findReplaceH = (
q[xah]=>q[fgcr],
q[that]=>q[hccg],
);

# $useRegexQ has values 1 or 0. If 1, inteprets the pairs in %findReplaceH
# to be regex.
my $useRegexQ = 0;

# in bytes. larger files will be skipped
my $fileSizeLimit = 500 * 1000;

#-- globals --

$folderPath =~ s[/$][]; # for example: '/home/joe/public_html'
$backupFolderPath =~ s[/$][]; # for example: '/tmp/joe_back';

$folderPath =~ m[/(\w+)$];
my $previousDir = $`;   # for example: '/home/joe'
my $lastDir = $1;   # for example: 'public_html'
my $backupRoot = $backupFolderPath . '/' . $1; # for example: '/tmp/joe_back/public_html'

my $refLargeFiles = [];
my $totalFileChangedCount = 0;

#-- subroutines --

# fileFilterQ($fullFilePath) return true if file is desired.
sub fileFilterQ ($) {
        my $fileName = $_[0];

        if ((-s $fileName) > $fileSizeLimit) {
                push (@$refLargeFiles, $fileName);
                return 0;
        };
        if ($fileName =~ m{\.html$}) {
print "processing: $fileName\n";
return 1;};

##        if (-d $fileName) {return 0;}; # directory
##        if (not (-T $fileName)) {return 0;}; # not text file

        return 0;
};

# go through each file, accumulate a hash.
sub processFile {
        my $currentFile = $File::Find::name; # full path spect
        my $currentDir = $File::Find::dir;
        my $currentFileName = $_;

        if (not fileFilterQ($currentFile)) {
                return 1;
        }

# open file. Read in the whole file.
        if (not(open FILE, "<$currentFile")) {die("Error opening file: 
$!");};
        my $wholeFileString;
        {local $/ = undef; $wholeFileString = <FILE>;};
        if (not(close(FILE))) {die("Error closing file: $!");};

# do the replacement.
        my $replaceCount = 0;

        foreach my $key1 (keys %findReplaceH) {
                my $pattern = ($useRegexQ ? $key1 : quotemeta($key1));
                $replaceCount = $replaceCount + ($wholeFileString =~ 
s/$pattern/$findReplaceH{$key1}/g);
        };

        if ($replaceCount > 0) { # replacement has happened
                $totalFileChangedCount++;
# do backup
  # make a directory in the backup path, make a backup copy.
                my $pathAdd = $currentDir; $pathAdd =~ s[$folderPath][];
                mkpath("$backupRoot/$pathAdd", 0, 0777);
                copy($currentFile, 
"$backupRoot/$pathAdd/$currentFileName") or
                    die "error: file copying file failed on 
$currentFile\n$!";

# write to the original
  # get the file mode.
                my ($mode, $uid, $gid) = (stat($currentFile))[2,4,5];

  # write out a new file.
                if (not(open OUTFILE, ">$currentFile")) {die("Error 
opening file: $!");};
                print OUTFILE $wholeFileString;
                if (not(close(OUTFILE))) {die("Error closing file: $!");};

  # set the file mode.
                chmod($mode, $currentFile);
                chown($uid, $gid, $currentFile);

                print "-----^$*%$@#-------------------------------\n";
                print "$replaceCount replacements made at\n";
                print "$currentFile\n";
        }

};

#-- main body --

find(\&processFile, $folderPath);

print "--------------------------------------------\n\n\n";
print "Total of $totalFileChangedCount files changed.\n";

if (scalar @$refLargeFiles > 0) {
        print "The following large files are skipped:\n";
        print Dumper($refLargeFiles);
}

__END__

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