Objective: Find all lines in a file that only contain alpha characters and delete or replace.

Sample contents of file.

 Z2j2NH23
 VTQnPwSS
 hFbxgvFt
 VSVR8v3F
 GPrP4zo

The following sed command works for our objective.

sed s/[[:alpha:]]\{8\}/ALPHAONLY/g file.txt

The part in the [] tells sed to search for any alpha characters a-Z, the part in bold \{8\} tells it to search 8 spaces out (Change if needed) and ALPHAONLY is what alpha line will get substituted to.

sed s/[[:alpha:]]\{8\}/ALPHAONLY/g

Returns

Z2j2NH23
ALPHAONLY 
ALPHAONLY 
VSVR8v3F
GPrP4zo9

You can run the same basic syntax in VI

Search and replace

:%s/[[:alpha:]]\{8\}/ALPHAONLY/g

Or to delete the lines

:%d/[[:alpha:]]\{8\}/d

You can also change [[:alpha:]] for [[:digit:]] if you want to search for numbers instead.

This is a Vim (Vi IMproved) cheat sheet, listing some useful, essential and most often used Vim commands. Most of the information was acquired here.

Vi is a command line text editor. To use it, from command line type in vi followed by the file name you want to edit.

Example:

vi filename.txt

Working with files
Vim command	Action
:e filename	Open a new file. You can use the Tab key for automatic file name completion, just like at the shell command prompt.
:w filename	Save changes to a file. If you don’t specify a file name, Vim saves as the file name you were editing. For saving the file under a different name, specify the file name.
:q	Quit Vim. If you have unsaved changes, Vim refuses to exit.
:q!	Exit Vim without saving changes.
:wq	Write the file and exit.
:x	Almost the same as :wq, write the file and exit if you’ve made changes to the file. If you haven’t made any changes to the file, Vim exits without writing the file.
Moving around in the file
These Vim commands and keys work both in command mode and visual mode.
Vim command	Action
j or Up Arrow	Move the cursor up one line.
k or Down Arrow	Down one line.
h or Left Arrow	Left one character.
l or Right Arrow	Right one character.
e	To the end of a word.
E	To the end of a whitespace-delimited word.
b	To the beginning of a word.
B	To the beginning of a whitespace-delimited word.
0	To the beginning of a line.
^	To the first non-whitespace character of a line.
$	To the end of a line.
H	To the first line of the screen.
M	To the middle line of the screen.
L	To the the last line of the screen.
:n	Jump to line number n. For example, to jump to line 42, you’d type :42
Inserting and overwriting text
Vim command	Action
i	Insert before cursor.
I	Insert to the start of the current line.
a	Append after cursor.
A	Append to the end of the current line.
o	Open a new line below and insert.
O	Open a new line above and insert.
C	Change the rest of the current line.
r	Overwrite one character. After overwriting the single character, go back to command mode.
R	Enter insert mode but replace characters rather than inserting.
The ESC key	Exit insert/overwrite mode and go back to command mode.
Deleting text
Vim command	Action
x	Delete characters under the cursor.
X	Delete characters before the cursor.
dd or :d	Delete the current line.
Entering visual mode
Vim command	Action
v	Start highlighting characters. Use the normal movement keys and commands to select text for highlighting.
V	Start highlighting lines.
The ESC key	Exit visual mode and return to command mode.

Editing blocks of text
Note: the Vim commands marked with (V) work in visual mode, when you’ve selected some text. The other commands work in the command mode, when you haven’t selected any text.
Vim command	Action
~	Change the case of characters. This works both in visual and command mode. In visual mode, change the case of highlighted characters. In command mode, change the case of the character uder cursor.
> (V)	Shift right (indent).
< (V)	Shift left (de-indent).
c (V)	Change the highlighted text.
y (V)	Yank the highlighted text. In Windows terms, “copy the selected text to clipboard.”
d (V)	Delete the highlighted text. In Windows terms, “cut the selected text to clipboard.”
yy or :y or Y	Yank the current line. You don’t need to highlight it first.
dd or :d	Delete the current line. Again, you don’t need to highlight it first.
p	Put the text you yanked or deleted. In Windows terms, “paste the contents of the clipboard”. Put characters after the cursor. Put lines below the current line.
P	Put characters before the cursor. Put lines above the current line.
Undo and redo
Vim command	Action
u	Undo the last action.
U	Undo all the latest changes that were made to the current line.
Ctrl + r	Redo.
Search
Vim command	Action
/pattern	Search the file for pattern.
n	Scan for next search match in the same direction.
N	Scan for next search match but opposite direction.

Editor Commands

All these commands can be added to your vimrc file so they are always available when you start vim. To use them while in the editor, hit “esc then :”.

Enable Colorsheme (you can replace “default” with any of the themes installed. i.e. delek, elflord, evening, etc.)

colorscheme default

Turn Syntax On/Off

syntax on
syntax off

Highlight searched word

Note: you can also use # and * to search for the word your cursor is on.

Enable

set hlsearch

Disable

nohlsearch
noh

Incredigeek

Tag Archives: vim

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