Question

I have the following string:

E E E 11 5 E 3 4

I need to be able to strip all “E” characters that go before the numbers. So that the output would be like this:

11 5 E 3 4

The number of first “E” can be different, so it can be either “E E” or “E E E E” etc.
How can I do it with SED? If possible, with alternative shell utils.

Answer 1

sed 's/^[E ]*\([0-9]\)/\1/'

This will replace all E’s and spaces before the first digit on a line, and that first digit, with the first digit.

The caveat would be that this doesn’t work on lines consisting only of E’s and spaces; I assumed from the wording that the removal is to be done only if there are numbers on the line. To support the case with only E’s simply use s/^[E ]*// for the program.