Find lines containing two strings

Shell Programming and Scripting
1

How can i find lines which contains two strings (or two charcters) let say "ABC" and "DEF".

Line: SEFGWN;BVABCFSDFBDEF

2 
grep "ABC.*DEF" urfile

or

grep ABC urfile |grep DEF
3

out_file lets say consist of ur SEFGWN;BVABCFSDFBDEF

sed '/ABC/!d;/DEF/!d' out_file
awk '/ABC.*DEF/' out_file
4 
awk '/ABC/&&/DEF/' myfile