~ / ex / substitutelesson 4/7

Substitute: :s, ranges and flags

Replace text on a line, in a range or everywhere, with & for the whole match.

?how it works

:s/old/new/ replaces the first old on the cursor line with new. Flags after the last slash change that:

g replaces every match on the line, not just the first
c asks before each one: y yes, n no, a all the rest, q quit

Put a range in front to go beyond one line: :%s/old/new/g is the whole file, :'<,'>s/… the selection, :3,8s/… lines 3 to 8.

In the replacement, & stands for whatever matched, so :s/\d\+/[&]/g wraps every number in brackets. Write \& for a real ampersand. The pattern is a search pattern: \d\+ is "one or more digits", \<word\> matches word only as a whole word.

The usual surprise: without g, only the first match on each line changes.

⌨keys

`:s/{old}/{new}/`	replace the first match on the line
`:s/{old}/{new}/g`	replace every match on the line
`:%s/{old}/{new}/g`	replace every match in the file
`:'<,'>s/{old}/{new}/`	replace in the selected lines
`&`	in the replacement: the whole match
`\&`	in the replacement: a literal &

Nin neovim

Neovim previews a substitution live in the buffer while you type it (the 'inccommand' option, nosplit by default). This editor only highlights the matches.

4 drills

Every match on this line: Replace every occurrence on the cursor line, and only on that line, with one :s command. Don't forget the flag that means "all of them".
The whole file: Make the replacement on every line of the file with one :%s command.
Just one part of the file: Only the paragraph with the cursor should change. Select it with vip and press : so the substitution gets the '<,'> range.
Reuse the match with &: Change every match in the file using & in the replacement to stand for the matched text (or \& for a literal ampersand).

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