I always struggle to remember things that I don’t use often. Here is my attempt to keep my knowledge somewhere else than in my head.
One of them is specific to vim.

How to search a specific string pattern inside a project and replace all its occurences easily.

Let’s start with the initial statement, I want to replace all the linux occurences by OpenBSD.

Find files that validate the pattern predicate

Run:
:vimgrep /linux/gj **/*

• **/* to search on all files recursively
• g flag to search for all occurences in each line
• j flag to avoid vim to jump automatically on the first occurence

Once the command ran, vim will populate the quickfix list with all the linux occurences. To see the list, run :copen.

Replace or subsitute all the linux occurences

Here comes vim’s super power, running a command for each line in the quickfix list.

Run:
:cfdo %s/linux/OpenBSD/gc | update

• %s/linux/OpenBSD is the subsitute pattern
• g flag replaces all occurences in each line
• c flag asks to confirm each subsitution
• update to make sure the file is saved before moving to the next one

For more information on those previous commands, you can try:

• :help vimgrep
• :help cfdo

All of these info are essentially copied from a stackexchange comment.

Thx.