How to rename a file in linux by removing certain characters from the file name?

Question

How can I rename a file in linux to strip out certain characters from the file name?

For example,

My123File.txt to be renamed to My123.txt

Answer 1

If you're okay with just wildcards (not full regexes), then you might try something like

f='My123File.txt'
mv $f ${f/File/}

This type of shell expansion is documented here.

If you really need regexes, try

f='My123File.txt'
mv $f $(echo $f | sed -e 's/File//')