First you need to make sure you have installed vim editor
#apt-get install vim-full
This will complete the installation
vimdiff [options] file1 file2 [file3]
You may also use "gvimdiff" or "vim -g". The GUI is started then.You may also use "viewdiff" or "gviewdiff". Vim starts in readonly mode then."r" may be prepended for restricted mode
If you want to open files use the following command
vimdiff file1 file2
vim -d file1 file2
If you want to open vertical splits for your files use the following command
vimdiff -O file1 file2
If you want to open horizontal splits for your files use the following command
vimdiff -o file1 file2
If you want to open files in perticular directory use the following command.Vim first append the file name of the first argument to the directory name to find the file.
vimdiff file1 file2 [file3 [file4]]
vim -d file1 file2 [file3 [file4]]
do -- Get changes from other window into the current window.
dp -- Put the changes from current window into the other window.
]c -- Jump to the next change.
[c -- Jump to the previous change.
Ctrl W + Ctrl W -- Switch to the other split window.
:diffupdate -- diff update
:syntax off -- syntax off
zo -- open folded text
zc -- close folded text
You can also use tkdiff,meld and xfdiff4 as an alternative