Search and replace uppercase letters with lowercase letters

Question

I have bunch of strings that starts with uppercase letters. I want to change uppercase letters with lowercase letters. Strings are not aligned so visual block mode is not an option. Is it possible to use substitute to do this?

Before:

'Readable & writeable outside of effects'
'Multiple signal reads in same effect should only register once'

After:

'readable & writeable outside of effects'
'multiple signal reads in same effect should only register once'

Answer 1

You can use the \l or the ´\L´ operator in the substitution:

e.g.:

:%s/^\w\+/\l&/

will substitute the first letter of the first words of each line to its lowercase version.

:%s/'\(\_[^']*\)'/'\l\1'/g

will substitute the first letter of a quoted string to its lowercase version

Answer 2

You can do this with the gu command and a motion: ggguG. To make everything uppercase, use: gggUG. Explanation (with mnemonic devices):

1. gg go to the first row.
2. gu go lowercase from here...
3. G to the end of the file.