Answer:
egrep 41[0-9][0-9][0-9] addresses.txt
Explanation:
Unfortunately I was not able to find the addresses.txt file, however I will explain the usage of the egrep command and the answer given.
egrep is a unix/linux command derived from grep, named after its function:
"Globally search for a Regular Expression and Print matching lines"
the difference with "grep" is that "egrep" allows extended regular expressions, for more complex search patterns.
egrep syntax is as follows:
egrep PATTERN [FILE...]
where PATTERN is the expression to search for, it can be as complex as desired, from a single character, to an expression combining range of numbers, wildcards, non-printable characters, and more.
and FILE is one or more files to search and obtain the PATTERNS.
Finally, regarding to this question, the answer given is:
egrep 41[0-9][0-9][0-9] addresses.txt
We assume the zip code is composed of five consecutive numbers, so our proposed pattern states that the first two numbers are 4 and 1, as requested, and then three more characters within the range 0 to 9.
It will return all the lines in addresses.txt containing a five-digit number starting with 41.
