Using patch and diff commands

Creating patches with diff

Using diff is simple when you are working with single files. To create a patch for a single .
diff -u file1.txt  new.txt  > new_file.patch

For  the directory, use following command:
diff -rupN  directory1/   directory2/   >  dir.patch




Apply  patch  

To apply a patch to a single file, change to the directory where the file is located and call patch:

patch  < dir.patch

you can specify the file on the command line:

patch  file.txt < dir.patch

To remove a patch, use the -R flag, 

patch -R file.txt < file.patch