How can I check a file for a string if missing the string automatically add it for example Input Input file test.txt this is a test text for testing purpose this is a test for testing purpose this is a test for testing purpose this is a test text for testing purpose I would like to add "text" to all the lines Desired Output this is a test text for testing purpose this is a test text for testing purpose this is a test text for testing purpose this is a test text for testing purpose Is it possible? many thanks in advance Hi guys thanks for all the help, for my case is not that simple. I wont know which line will be different and in the middle string it will not only have a single string. i will give a clearer case Input file test.txt Group: IT_DEPT,VIP Role: Viewer Dept: IT Group: IT_DEPT,VIP Dept: IT Group: FINANCE LOAN VIEWER Role: Viewer Dept: FINANCE Group: FINANCE LOAN VIEWER Dept: FINANCE Desired output file test2.txt Group: IT_DEPT,VIP Role: Viewer Dept: IT Group: IT_DEPT,VIP Role: - Dept: IT Group: FINANCE LOAN VIEWER Role: Viewer Dept: FINANCE Group: FINANCE LOAN VIEWER Role: - Dept: FINANCE So those that are missing "Role:" will be added "Role: - ", hope this clear things out, thanks in advance again