# grep -v "Word" --- To remove the line containing the specific word form output
# grep -w "Word --- Filter lines contains specific word
# grep -nrwi address /etc --- Find word "address" in files of /etc directory and subdirectores recursively with line number
# grep -E "abc|xyz" file1 --- To display all lines in the file1 file that match either the abc or xyz string
# grep -B 1 "1 received" test.txt --- Print Matched line and line above the mathed line