Remove empty lines in a text file via grep

with awk, just check for number of fields. no need regex

$ more file
hello

world

foo

bar

$ awk 'NF' file
hello
world
foo
bar

Try the following:

grep -v -e '^$'

Here is a solution that removes all lines that are either blank or contain only space characters:

grep -v '^[[:space:]]*$' foo.txt

(And if you really want to do it in sed, then: sed -e /^$/d FILE)

(And if you really want to do it in awk, then: awk /./ FILE)

Related