Remove empty lines in a text file via grep

grep . FILE

(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)

Try the following:

grep -v -e '^$'

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

$ more file
hello

world

foo

bar

$ awk 'NF' file
hello
world
foo
bar

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

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

If removing empty lines means lines including any spaces, use:

grep '\S' FILE

For example:

$  printf "line1\n\nline2\n \nline3\n\t\nline4\n" > FILE
$  cat -v FILE
line1

line2

line3

line4
$  grep '\S' FILE
line1
line2
line3
line4
$  grep . FILE
line1
line2

line3

line4

See also:

• How to remove empty/blank lines (including spaces) in a file in Unix?
• How to remove blank lines from a file in shell?
• With sed: Delete empty lines using sed
• With awk: Remove blank lines using awk