grep 'abc|ghi' data.txt #ng
grep 'abc\|ghi' data.txt
sed -n '/abc|ghi/p' data.txt #ng
sed -n '/abc\|ghi/p' data.txt
awk '/abc|ghi/' data.txt
perl -ne '/abc|ghi/ && print' data.txt
perl -ne 'print if /abc|ghi/' data.txt
perl -ne 'if(/abc|ghi/){print}' data.txt