| grep '^..$' filename | Match all lines with exactly two characters |
| grep '^.\{12\}$' filename | Match all lines with exactly 12 characters |
| grep '^.\{12,\}$' filename | Match all lines with at least 12 characters |
| grep '^.\{7,12\}$' filename | Match all lines with at least 7 and less than or equal to 12 characters |
| grep -v foobar filename | Match all lines in filename that do not match foobar |
