Vim / Neovim Commands

Command :substitute (:s)

1. Basic syntax: :[range]s/{pattern}/{replace}/[flags] [count]


• range: where to apply.


1. no specifier: current line.


2. .: current line.


3. $: last line.


4. line1,line2: range from line1 to line2, both inclusive, first line is indexed 1 not 0.


5. %: whole file.


6. 1,$: whole file.


7. .,$: from current line to the end.


8. '<,'>: visual selection (start / end).


9. line+N: N lines after line.


10. line-N: N lines before line.




• pattern: regex to find.


1. \< and \>: word boundaries.


2. ^word: start with word.


3. word$: end with word.


4. .: match exactly one character except newline.


5. .*: greedy match.


6. .\{-}: non-greedy match.


7. \_.: match exactly one character including newline.


8. \: escape special character.


9. \n: match newline.


10. \(<content>\): match a group.




• replace: what to replace.


1. \r: newline.


2. \t: tab.




• flags: behaviors.


1. g: replace all matches per line.


2. c: confirm each substitution.


3. i: case-insensitive mode.


4. I: case-sensitive mode.


5. n: no change, only highlight.


6. e: no error if nothing found.




• count: max subs per line (rarely used).

Vim Commands on Files

1. Commonly used ones:



Symbol	Meaning	Example
%	The current file name	:! echo % or :echo expand('%') gets main.c
%:p	Full absolute path of the current file	:! echo %:p or :echo expand('%:p') gets /home/user/proj/src/main.c
%:p:h	Directory (head) of the current file	:! echo %:p:h or :echo expand('%:p:h') gets /home/user/proj/src
%:t	Tail (basename only)	:! echo %:t or :echo expand('%:t') gets main.c
%:r	Root (filename without extension)	:! echo %:r or :echo expand('%:r') gets main
%:e	Extension name only	:! echo %:e or :echo expand('%:e') gets c

Using External sed in Vim

1. Basic syntax: :[range]!sed 's/{pattern}/{replace}/{flags}'


• range: which lines to filter through sed.


1. .: current line only.


2. %: entire file (most common).


3. '<,'>: visual selection.


4. 1,10: lines 1 through 10.


5. .,$: current line to end of file.




• Key differences from Vim's :s:


1. Spawns external process (slower).


2. Replaces buffer content with sed output.


3. Uses sed regex syntax (slightly different from Vim).


4. No access to Vim registers or special features.


5. Single undo operation for entire filter.






2. Common use cases:



Task	Vim Command	Equivalent Native Vim
Simple substitution	:%!sed 's/foo/bar/g'	:%s/foo/bar/g (faster)
Delete empty lines	:%!sed '/^$/d'	:g/^$/d (better)
Delete lines with pattern	:%!sed '/pattern/d'	:g/pattern/d
Print specific lines	:%!sed -n '5,10p'	:5,10 (view only)
Insert line before match	:%!sed '/pattern/i\New line'	:g/pattern/norm! ONew line
Append line after match	:%!sed '/pattern/a\New line'	:g/pattern/norm! oNew line
Multiple operations	:%!sed 's/a/A/g; s/b/B/g'	:%s/a/A/g | %s/b/B/g
Case conversion (uppercase)	:%!sed 's/.*/\U&/'	:% norm! gUU or :%s/.*/\U&/



3. Advanced sed patterns:


• Regex differences from Vim:


1. \+: one or more (in basic sed, or use sed -E for +).


2. \?: zero or one (in basic sed, or use sed -E for ?).


3. \|: alternation (in basic sed, or use sed -E for |).


4. \( \): capture groups (always escaped in basic sed).


5. &: reference the entire match in replacement.


6. \1, \2: backreferences (same as Vim).




• Extended regex mode: :%!sed -E 's/(foo)(bar)/\2\1/'




4. Practical examples:



Description	Command
Filter current line through sed	:.!sed 's/old/new/g'
Filter visual selection	:'<,'>!sed 's/old/new/g'
Remove trailing whitespace	:%!sed 's/[[:space:]]*$//'
Number all lines	:%!sed = | sed 'N;s/\n/\t/'
Double-space document	:%!sed G
Delete HTML tags	:%!sed 's/<[^>]*>//g'
Convert DOS to Unix line endings	:%!sed 's/\r$//'
Swap first two fields (CSV)	:%!sed -E 's/([^,]*),([^,]*)/\2,\1/'



5. When to use sed vs native Vim commands:



Use sed when...	Use Vim's :s when...
You need a specific sed script you already have	Doing interactive editing (faster, better undo)
Using complex sed-specific features	Performance matters (no process spawning)
Piping through multiple filters	Need Vim registers or expression evaluation
Combining with other Unix tools	Working with visual selections frequently
Testing sed script for shell use	General text editing (native Vim is superior)



6. Combining sed with other filters:


• :%!sed 's/foo/bar/' | grep bar: substitute then filter.


• :%!sort | sed 's/^/- /': sort lines, then add bullet.


• :%!sed 's/</\&lt;/g; s/>/\&gt;/g': HTML escape.




7. Important note: In most cases, native Vim commands are preferred over external sed for better performance, undo granularity, and integration with Vim's features.