Write a script named search dna that will expect on the command line a single argument which is…

Write a script named search dna that will expect on the command line a single
argument which is the name of a file containing multiple DNA strings, each on
a single line with no white space characters of any kind except for the terminating
newline character at the end of the line. Each line is just a sequence
of the letters a, c, g, and t. This script will print each line in which the 4th
3-letter sequence is repeated twice later in the line at starting positions that are
multiples of three apart. For example, the string below, which is broken into
groups of three letters for ease or reading
acg ttt ggg ccc agc tct ccg ccc tca cac aca ccc cgg ggt
satisfies this requirement, since ccc is the 4 th three-letter sequence and it reoccurs
twice at positions that are multiples of three apart, whereas this one does
not:
acg ttt ggg ccc agc tct ccg gcc cca cac aca ccc cgg ggt
because, although ccc occurs twice later in the line, the first reoccurrence is
not a multiple of three positions from the first one.
2
Write a script named dollars that prints all and only the lines in the standard
input stream that contain monetary amounts of at least one dollar, expressed in
dollars and cents. There is no upper limit on the amounts you may find in the
file. Dollar amounts in excess of $999.99 will have commas in the number, such
as $32,478,120.52 or $906,201,777,528.10. Numbers should not have spaces or
any other characters in them other than the dollar sign, comma, decimal point,
and digits. Amounts should not be matched if they start with a leading 0, or
are missing cents, or contain invalid characters. This program does not issue
any error messages.