How to edit a text file in Linux Redhat
Log into your Redhat server using PUTTY or similar application
To open a file with the standard text editor type vi <filename> at a shell prompt
To add text, press 'i' (for Insert mode). This will allow you to make modifications
To exit insert mode, press 'Esc', vi will revert to Normal mode
To exit vi, press ':' (which is the vi command mode) and press 'q' then 'Enter'
If you have made changes to the text file that you want to save, press ':' and type 'w' then 'q' to write your changes to the file and exit the application
If you accidentally made changes to a file and you want to exit vi without saving the changes, type ':' and then type 'q' followed by '!', which exits without saving changes.
More information about using vi can be found by typing 'man vi' at a shell prompt.