:wq vs :x in VIM
:wq
stands for write and quit:x
stands for exit
The difference between those twos is very simple: :x
saves changes to the file only it it has been modified, while
:wq
changes the modification time no matter what.
Both can be used with command line arguments, i.e. to remove 2nd line in a file:
vim file.name +"2d|x