Vim global substitution doesn't substitute all matches in a line

Question

Sometimes my global substitutions don't substitute all matches in a line. It is confirmed by the fact that I can see it when I do substitutions with confirmation, a match is found in a line with multiple possible matches, but then it goes to another line.

I use the g or gc parameters operating on the entire file with %.

On this file:

hello hello
hello
hello hello hello
hello

If I do %s/hello/goodbye/g I get:

goodbye hello
goodbye
goodbye hello hello
goodbye

All I have in my .vimrc about search/replace is:

set hlsearch
set ignorecase
set incsearch

Answer 1

Maybe you, or a plugin, had enabled the option 'gdefault'. This option adds the flag g automatically whenever you perform a substitution.

So, when you manually add the flag g while 'gdefault' is enabled, it's as if you had 2 g flags which has the same effect as none. Therefore, Vim only substitutes the first occurrence of the pattern on every line.

By default, this option is disabled, but to make sure it is, you could add at the end of your vimrc: set nogdefault.

Alternatively, if you suspect a plugin might have enabled the option, you could track it down with: verb set gd?

Or you could get used to the option which means that when you want to substitute all the occurrences of a pattern, you don't add the g flag (because gdefault already did it), and when you want to only substitute the 1st occurrence of the pattern on a line, you add the g flag (because 2 g flags is the same as none).

Answer 2

No need to change any settings. The syntax is wrong. You should use all %'s as shown below:

hello hello
hello
hello hello hello
hello

:%s%hello%goodbye%g

goodbye goodbye
goodbye
goodbye goodbye goodbye
goodbye

Usually you use / when doing specific line changes, e.g: something like:

:1,3 s/hello/goodbye/g

goodbye goodbye
goodbye
goodbye goodbye goodbye
hello