I have got a question. How to do this? I mean AND expression in regex.

List all the files in current directory that do not contain the words use AND take.

Thx.

Assuming you want an answer rather than a theory, something like

for f in *; do
  grep use "$f" >/dev/null && continue
  grep take "$f" >/dev/null && continue
  # file contains neither if we get to here; report its file name
  echo "$f"
done

From the top of my head, I would use something like

grep -L use $(grep -L take *.txt)

Use egrep, search for $var1 OR $var2:

egrep "[$var1]|[$var2]" file

egrep -v "[$var1]|[$var2]" file

egrep "$var1.*$var2|$var2.*$var1" file

egrep -v "$var1.*$var2|$var2.*$var1" file

i think OP means the words "use" and "take" should not be in the file. So the egrep solution will not work is "use" and "take" are on separate lines.

Sorry, just awake , I have to read the question thoroughly.

Regards

I guess I misinterpreted the OP, now here is my supersilly superuseless use of cat and pipe...

for x in *.txt;do cat $x|tr "\n" " "|egrep '(use.*take|take.*use)'&>/dev/null; [ $? == 1 ] && echo $x;done