grep -3
  -C [NUM], -NUM, --context[=NUM]
  Print NUM lines (default 2) of 
  output context.

grep -A3
  -A NUM, --after-context=NUM
  Print NUM lines of trailing context 
  after matching lines.

grep -B3
  -B NUM, --before-context=NUM
  Print NUM lines of leading context 
  before matching lines.