grep -i
ignore case. do not distinguish between upper and lower
grep -v
invert match, grep prints the lines that do not match the pattern
grep -c
print the number of matches
grep -l
print the name of each file, instead of printing each line
grep -L
prints the name of each file that DOESN’T contain the pattern
grep -n
prefix each matching line wth the number of the line
grep -h
for multi-file searches, suppress output of filenames