Re: The usage of \L of s in sed?

[Bob Proulx]

Peng Yu wrote:
> I still don't understand how to use \L in sed after reading the
> manual. Could you please show me some example on how to use it?
> 
> echo "ABC" | sed -r -e 's/A/\L/g'

Start off by doing the replacement that you want to lower (or upper)
case.  In this example I will use '&' to replace with the full input
match.

  $ echo "ABC" | sed -r -e 's/B/&/g'
  ABC

Then bracket your replacement with the translation you want.

  $ echo "ABC" | sed -r -e 's/B/\L&\E/g'
  AbC

You can do some of one and some of another.  This uses numbered
backreferences and brackets them with upper and lower case
translations.

  $ echo "Abc" | sed -r -e 's/^(.)/\1/g'
  Abc

  $ echo "Abc" | sed -r -e 's/^(.)(.)(.)/\L\1\U\2\E\3/g'
  aBc

Hope that helps.
Bob