Hi,
How do I remove the lines where special characters or Unicode characters appear?
The following query does work but I wonder if there is a better way.

cat test.txt | egrep -v '\)|#|,|&|-|\(|\\|\/|\.'

The following lines show that my query is incomplete.

Warning: The word "*Khan" is invalid. The character '*' (U+2A) may not appear at the beginning of a word. Skipping word.
Warning: The word "Khan]" is invalid. The character ']' (U+5D) may not appear at the end of a word. Skipping word.
Warning: The word "Khandewa;l" is invalid. The character ';' (U+3B) may not appear in the middle of a word. Skipping word.
Warning: The word "[khanna" is invalid. The character '[' (U+5B) may not appear at the beginning of a word. Skipping word.
Warning: The word "Khar**Closed" is invalid. The character '*' (U+2A) may not appear in the middle of a word. Skipping word.
Warning: The word "Khelani]" is invalid. The character ']' (U+5D) may not appear at the end of a word. Skipping word.
Warning: The word "Khwaja[physician]" is invalid. The character '[' (U+5B) may not appear in the middle of a word. Skipping w
ord.
Warning: The word "Kids@play" is invalid. The character '@' (U+40) may not appear in the middle of a word. Skipping word.

To eliminate all but printable characters:
There's also [:punct:] which are all punctuation characters. Or you can search for anything that doesn't have a normal letter or number: