vim

Vi IMproved, a programmer's text editor, providing several modes for different kinds of text manipulation. Pressing i enters edit mode. <Esc> goes back to normal mode, which doesn't allow regular text insertion.

• Open a file:

vim {{file}}

• Enter text editing mode (insert mode):

<Esc>i

• Copy ("yank") or cut ("delete") the current line (paste it with P):

<Esc>{{yy|dd}}

• Undo the last operation:

<Esc>u

• Search for a pattern in the file (press n/N to go to next/previous match):

<Esc>/{{search_pattern}}<Enter>

• Perform a regex substitution in the whole file (from the start, 1, to the end, $):

<Esc>:1,$s/{{pattern}}/{{replacement}}/g<Enter>

• Save (write) the file, and quit:

<Esc>:wq<Enter>

• Quit without saving:

<Esc>:q!<Enter>