Hi
Kindly give me the exact usage of grep such that it should display only lines with single words.
In awk its cat filename|awk 'NF<2 {print $0}' will display lines with single word only

This should get you what you want most of the time:

grep -E "^[A-Za-z0-9]+$" filename

$ grep "^[^ ]*$" infile.txt

Example:

$ cat infile.txt
This is a test
file
to test how
grep can
grep the
lines
with only one
word.

$ grep "^[^ ]*$" infile.txt
file
lines
word.

Luke Chi