regex - upper- to lower-case using sed

Question

I'd like to change the following patterns:

getFoo_Bar

to:

getFoo_bar

(note the lower b)

Knowing neither foo nor bar, what is the replacement pattern?

I started writing

sed 's/(get[A-Z][A-Za-z0-9]*_)([A-Z])/1

but I'm stuck: I want to write "2 lower case", how do I do that?

Maybe sed is not adapted?

Answer 1

To change getFoo_Bar to getFoo_bar using sed :

echo "getFoo_Bar" | sed 's/^(.{7})(.)(.*)$/1l23/'

The upper and lowercase letters are handled by :

• U Makes all text to the right uppercase.
• u makes only the first character to the right uppercase.
• L Makes all text to the right lowercase.
• l Makes only the first character to the right lower case. (Note its a lowercase letter L)

The example is just one method for pattern matching, just based on modifying a single chunk of text. Using the example, getFoo_BAr transforms to getFoo_bAr, note the A was not altered.