Open a non empty file, go to a specific row and column and edit(overwrite)

Hello, I want to open a file (from command line), say 'cylds.bc', then navigate to a specific line and edit that line. These are the contents of the file:

# BC_SLIPW
PATCH    1 1
NAME     SolidWall
#
say i wanted to go to second line and change the number 1 1 to 2 1 . How can I do that?

Answer 1

[Andrew]

you could do something with textscan and strncmp

for instance:

fid = fopen('cylds.bc','r+');  %open file for reading and writing

data=textscan(fid,'%s')  %read file as string

data=data{1};  %for some reason maybe someone can explain you need to do this to get to the data 

data(strncmp('PATCH',data,1)) = sprintf('%5s %5i %i','PATCH',2,1);

fprintf(fid,'%s',data);  %write the data to the file

fclose(fid);  %close file

Please note that I have not tested this so there may be a typo