Changing all occurrences in a folder


Regex Problem Overview

I need to do a regex find and replace on all the files in a folder (and its subfolders). What would be the linux shell command to do that?

For example, I want to run this over all the files and overwrite the old file with the new, replaced text.

sed 's/old text/new text/g' 

Regex Solutions

Solution 1 - Regex

There is no way to do it using only sed. You'll need to use at least the find utility together:

find . -type f -exec sed -i.bak "s/foo/bar/g" {} \;

This command will create a .bak file for each changed file.


  • The -i argument for sed command is a GNU extension, so, if you are running this command with the BSD's sed you will need to redirect the output to a new file then rename it.
  • The find utility does not implement the -exec argument in old UNIX boxes, so, you will need to use a | xargs instead.

Solution 2 - Regex

I prefer to use find | xargs cmd over find -exec because it's easier to remember.

This example globally replaces "foo" with "bar" in .txt files at or below your current directory:

find . -type f -name "*.txt" -print0 | xargs -0 sed -i "s/foo/bar/g"

The -print0 and -0 options can be left out if your filenames do not contain funky characters such as spaces.

Solution 3 - Regex

For portability, I don't rely on features of sed that are specific to linux or BSD. Instead I use the overwrite script from Kernighan and Pike's book on the Unix Programming Environment.

The command is then

find /the/folder -type f -exec overwrite '{}' sed 's/old/new/g' {} ';'

And the overwrite script (which I use all over the place) is

# overwrite:  copy standard input to output after EOF
# (final version)

# set -x

case $# in
0|1)        echo 'Usage: overwrite file cmd [args]' 1>&2; exit 2

file=$1; shift
new=/tmp/$$.new; old=/tmp/$$.old
trap 'rm -f $new; exit 1' 1 2 15    # clean up files

if "$@" >$new               # collect input
    cp $file $old   # save original file
    trap 'trap "" 1 2 15; cp $old $file     # ignore signals
          rm -f $new $old; exit 1' 1 2 15   # during restore
    cp $new $file
	echo "overwrite: $1 failed, $file unchanged" 1>&2
	exit 1
rm -f $new $old

The idea is that it overwrites a file only if a command succeeds. Useful in find and also where you would not want to use

sed 's/old/new/g' file > file  # THIS CODE DOES NOT WORK

because the shell truncates the file before sed can read it.

Solution 4 - Regex

Might I suggest (after backing up your files):

find /the/folder -type f -exec sed -ibak 's/old/new/g' {} ';'

Solution 5 - Regex

Example: replase {AutoStart} with 1 for all of the ini files under the /app/config/ folder and its child folders:

sed 's/{AutoStart}/1/g' /app/config/**/*.ini

Solution 6 - Regex

This worked for me (on mac terminal, on Linux you don't need '' -e):

sed -i '' -e 's/old text/new text/g' `grep 'old text' -rl *`

the command grep 'old text' -rl * lists all files in the working directory (and subdirectories) where "old text" exists. This then is passed in sed.

Solution 7 - Regex

If you are worried about clobbering files that you accidentally haven't considered, you can run grep with the recursive option first to see which files will be potentially changed:

grep -r 'searchstring' *

It's then not hard to put together something that will run the replacement on each of these files:

for f in $(grep -r 'searchstring' *)
    sed -i -e 's/searchstring/replacement/g' "$f"

(Only valid with GNU sed - adjustments would be needed for POSIX compatibility as the -i inplace option is a GNU extension):

Solution 8 - Regex

Might want to try my mass search/replace Perl script. Has some advantages over chained-utility solutions (like not having to deal with multiple levels of shell metacharacter interpretation).


use strict;

use Fcntl qw( :DEFAULT :flock :seek );
use File::Spec;
use IO::Handle;

die "Usage: $0 startdir search replace\n"
    unless scalar @ARGV == 3;
my $startdir = shift @ARGV || '.';
my $search = shift @ARGV or
    die "Search parameter cannot be empty.\n";
my $replace = shift @ARGV;
$search = qr/\Q$search\E/o;

my @stack;

sub process_file($) {
    my $file = shift;
    my $fh = new IO::Handle;
    sysopen $fh, $file, O_RDONLY or
        die "Cannot read $file: $!\n";
    my $found;
    while(my $line = <$fh>) {
        if($line =~ /$search/) {
            $found = 1;
    if($found) {
        print "  Processing in $file\n";
        seek $fh, 0, SEEK_SET;
        my @file = <$fh>;
        foreach my $line (@file) {
            $line =~ s/$search/$replace/g;
        close $fh;
        sysopen $fh, $file, O_WRONLY | O_TRUNC or
            die "Cannot write $file: $!\n";
        print $fh @file;
    close $fh;

sub process_dir($) {
    my $dir = shift;
    my $dh = new IO::Handle;
    print "Entering $dir\n";
    opendir $dh, $dir or
        die "Cannot open $dir: $!\n";
    while(defined(my $cont = readdir($dh))) {
            if $cont eq '.' || $cont eq '..';
        # Skip .swap files
            if $cont =~ /^\.swap\./o;
        my $fullpath = File::Spec->catfile($dir, $cont);
        if($cont =~ /$search/) {
            my $newcont = $cont;
            $newcont =~ s/$search/$replace/g;
            print "  Renaming $cont to $newcont\n";
            rename $fullpath, File::Spec->catfile($dir, $newcont);
            $cont = $newcont;
            $fullpath = File::Spec->catfile($dir, $cont);
        if(-l $fullpath) {
            my $link = readlink($fullpath);
            if($link =~ /$search/) {
                my $newlink = $link;
                $newlink =~ s/$search/$replace/g;
                print "  Relinking $cont from $link to $newlink\n";
                unlink $fullpath;
                my $res = symlink($newlink, $fullpath);
                warn "Symlink of $newlink to $fullpath failed\n"
                    unless $res;
            unless -r $fullpath && -w $fullpath;
        if(-d $fullpath) {
            push @stack, $fullpath;
        } elsif(-f $fullpath) {

if(-f $startdir) {
} elsif(-d $startdir) {
    @stack = ($startdir);
    while(scalar(@stack)) {
} else {
    die "$startdir is not a file or directory\n";

Solution 9 - Regex

for i in $(ls);do sed -i 's/old_text/new_text/g' $i;done 

Solution 10 - Regex

In case the name of files in folder has some regular names (like file1, file2...) I have used for cycle.

for i in {1..10000..100}; do sed 'old\new\g' 'file'$i.xml > 'cfile'$i.xml; done


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