# Open a file:
$ vim path/to/file
# Open a file at a specified line number:
$ vim +line_number path/to/file
# View Vim's help manual:
$ :help<Enter>
# Save and quit the current buffer:
$ :wq<Enter>
# Enter normal mode and undo the last operation:
# <ESC>u
# Search for a pattern in the file (press `n`/`N` to go to next/previous match):
$ /search_pattern<Enter>
# Perform a regular expression substitution in the whole file:
$ :%s/regular_expression/replacement/g<Enter>
# Display the line numbers:
$ :set nu<Enter>