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Replace strings in text file

4.7 | 25 ratings Rate this file 9 Downloads (last 30 days) File Size: 1.92 KB File ID: #18909 Version: 1.2

Replace strings in text file



25 Feb 2008 (Updated )

REPLACEINFILE replaces characters in ASCII file using PERL

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Easy and efficient way to replace strings in ASCII files.
For example replace commas ',' to points '.' in large data files for easier load.


This file inspired Make Inkscape Post Script Files Compatible With Psfrag In La Te X.

MATLAB release MATLAB 7 (R14)
Other requirements Made for Windows, for other platforms edit the path to perl on line 46
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Comments and Ratings (33)
24 Nov 2014 Paul Macey

19 Feb 2014 Steven

Steven (view profile)

I had trouble replacing some trouble when the string I wanted to replace had '.' symbol. I am using MATLAB 2013b on Ubuntu 12.04 kernel 3.2.0-58-generic.

I ran the function like this:
>> replaceinfile('.iq','.buf','file1.txt','file2.txt')

This function worked correctly for one line of my file (the one I wanted to change):

sOpt.suffix = '.iq';


sOpt.suffix = '.buf';

The problem occurred for this line (which I did not want to change):

sOpt.datadir = 'iqdata/';


sOpt.datadir = .bufdata/';

I found I had no problems if I ran the function either of the following ways:
>> replaceinfile('\.iq','\.buf','iqpro_setup.txt','test.txt')
>> replaceinfile('\.iq','.buf','iqpro_setup.txt','test.txt')

Maybe this is a trait of PERL, not sure. Thought I'd share on the off chance that anyone else runs into that problem.

Thanks for the code.

11 Nov 2013 Jose

Jose (view profile)

Works very well, I am using it to generate a batch of files from a single template. I am replacing two strings in a template and creating a file everytime. Is there a way to replace multiple strings in one shot?
The way I do it now is:
1. Open template, replace first string, save with new name.
2. Open new file, replace second string.

19 Sep 2013 Phillip

Great. This was just what I needed. I added a multiselect uidetfile beforehand so I could do a batch replace on a large number of files and it worked perfectly.
[files] = uigetfile('*.txt','multiselect','on');

cnt = length(files);

for i = 1:cnt
s = replaceinfile(oldStr,newStr,files{i});

15 May 2013 Kevin J. Delaney

Fantastic! Just what I was looking for & it works great.

11 Jan 2013 Kokop

Kokop (view profile)

Congrat! good script.
Only i have one question. how to use this script with multiples files? For example i have a several files in format txt in one directory, like: 31.txt, 32.txt, 33.txt... etc
there is a way to use this script for change in all the files the commas ',' to points '.'?
Thanks in advance for your help!

Comment only
12 Dec 2012 Simon Funder

Very neat script - exactly what I was looking for. One request for a modification though:

Is it possible to specify exact lines in the input file that the script shall apply to, so e.g. find and replace is only done in the first 10 lines of my input file?


30 Nov 2012 Julius

Julius (view profile)

When I want to replace the string "AB.12345" with "AB.54321", the function also replaces "AB-12345", which are also in the original ASCII file with "AB.54321". This was not my intention. Can the author fix this?

24 Jun 2012 maryam

maryam (view profile)

18 May 2012 Sebastian

Good job! Works great for me!

14 Nov 2011 ubuntu21 T

Ehsan suggested on 02 Jan 2011 to write the code for a sort of automatical switch between different OS. In my case, I have on my computer Windows and Ubuntu 10.04 Linux, so I have replaced the line

perlCmd = sprintf('"%s"',fullfile(matlabroot, 'sys\perl\win32\bin\perl'));


if findstr('glnx',lower(computer))
perlCmd = sprintf('"%s"',fullfile('/usr/bin/perl'));
else %assume it's windows otherwise
perlCmd = sprintf('"%s"',fullfile(matlabroot, 'sys\perl\win32\bin\perl'));

I have only tested on Ubuntu 10.04 Linux, with positive results on a 240 MB file. It works like a charm and very fast.

Comment only
29 Sep 2011 Jack

Jack (view profile)

18 Aug 2011 Fernando

Hello everybody!

Could somebody give me some help with this file? Perhaps and example or something like that. I am running the function with the text I want to replace but is says that there are no matches for my search. Also, does the format has to be a .bak file or could it be a .txt?

Thanks in advance for your help!

Comment only
18 Aug 2011 Adi Navve

Adi Navve (view profile)

Works great.
Just one suggestion, in case of calling the function with filenames without a full path the call fails if these files are not in the system path. How about adding support to this case by identifying it and building the path using "which" function?
Thanks for the submission.

04 Jul 2011 Lennart van Luijk

Works exactly like it's supposed to!

02 Jan 2011 Ehsan

Ehsan (view profile)

would be nice if there was a matlab/linux switch automatically change between

(matlabroot, 'sys\perl\win32\bin\perl')

28 Jun 2010 Johannes Schaffner

05 May 2010 Doug Hull

Doug Hull (view profile)

22 Apr 2010 Richard Holcombe

This doesn't seem to work at all for me. after running the program, the directory that contained the file now has its permissions set so that I cannot access the file, or even delete the directory containing the file. I don't know what happened to the text of the file because I can't access the file.

Comment only
21 Apr 2010 McLaren

AH! It was siple, / is a special character, it should be expressed with a \ in front as per the comment above!

...for the next user

Comment only
20 Apr 2010 McLaren

A host of alternative errors seem to plague me method of calling the function depending on varying my reference to a space as ' ', char(32) or 'char(32)':

??? Error using ==> replaceinfile at 64
Illegal division by zero at -e line 1, <> line 1.

??? Error using ==> replaceinfile at 64
Bareword found where operator expected at -e line
1, near "s///char"
syntax error at -e line 1, near "s///char"
Execution of -e aborted due to compilation errors.

Comment only
20 Apr 2010 McLaren


This may be an obvious error as I am just getting into Matlab,

when I call tthe function:
[s, msg] = replaceinfile('/', ' ', 'data.dat');

i get the error:
??? Error using ==> replaceinfile at 64
Can't do inplace edit on data.dat: File exists.

Any ideas?

I have to do several substitutions in sequence in order to be able process the data appropriately, i imagine doing this by:

[s, msg] = replaceinfile( '/' , ' ' , 'data.dat');
[s, msg] = replaceinfile( ',' , '. ' , 'data.dat');

should this work?

Comment only
01 Mar 2010 mark95tt

Seems to work great overall. Couldn't get it to replace the string '//' in my ascii file, though. Get this error:

Bareword found where operator expected at -e line 1, near "%/g"
(Missing operator before g?)
syntax error at -e line 1, next token ???
Execution of -e aborted due to compilation errors.

21 Jul 2009 boutonnet arnaud

'+' is a reserved symbol for regular expressions. One needs to put a '\'in front of it and then it works !

20 Jul 2009 boutonnet arnaud

... If the string contains the 'plus' symbol

20 Jul 2009 boutonnet arnaud

Very useful. One problem though: the function doesn't work if the string contains the symbol '+'

03 Jul 2009 Oleg Komarov

Oleg Komarov (view profile)

Works fine...don't know what happened :)

03 Jul 2009 Oleg Komarov

Oleg Komarov (view profile)

I have some problems with whitespaces, i want to replace tehm with a char, "X". but it places an "X" between every char.
20039 IAN43
replaceinfile(' ','X', myfile) --> 2X0X0X3X9X X XIXAXNX4X3
instead of 20039XXIAN43

Comment only
24 May 2009 John Peterson

Very nice. Could I find a Unicode version of this?

24 Aug 2008 Dennis M

very nice

22 Aug 2008 Butch Walker

Would be nice to have an option to replace 'first occurance' instead of automatically replacing all when the file has multiple matches and you dont want to replace them all. Otherwise, great script!

21 Aug 2008 Andy G

Pretty Slick!

17 Mar 2008 q w

03 Mar 2008

Fixed error if MATLAB path has whitespaces

16 Nov 2008 1.1

Now supports paths with spaces, forced overwrite of existing output file, corrected replaceing of '.' and '\'

08 Jan 2009 1.2

'-nobak' option to remove backup file, fixed help a little

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