Systems Programming Assignment 2: sed Solution

For this assignment, you will use sed, bash, and the other utilities you have used in class to create a program for use by a municipality for both redacting sensitive information from internal communi-cations, as well as simplifying and standardizing the format of these documents prior to their release and circulation. Your program should take the names of one or more files that are to be redacted as command line arguments.




This assignment requires only sed, bash, and the other utilities used so far in class. Do not use awk, Python, or any other languages/utilities.




Redaction and Substitution Rules







For all files specified, the following changes should be made in place. No other changes should be made to the file.




Driver’s License numbers begin with xx DL, where xx is a two-letter state code identifying the origin of the issuing state. Following this code is a space character, then a license number composed of at least 6 digits in length. For example, the following are all valid driver’s license numbers:



– TXDL 12345678




– VADL 123456




– WADL 1234567890




These numbers should be redacted by simply replacing the license number with a sequence of six X characters.




Credit Card Numbers Credit card numbers must be redacted, but it is desirable that the censored text still retain information suitable for the identification of both the type of card (i.e., the issuer), as well as its last four digits. Each card network specifies a unique first digit to the cards they issue, and typically contain 16 digits in total. American Express is an exception to this, in which the second number can only be a 4 or a 7, and the total number of digits is only 15. In summary:



– Visa cards: Begin with a 4 and have 16 digits




– Master Cards: Begin with a 5 and have 16 digits




– American Express cards: Begin with a 3, followed by a 4 or a 7, and have 15 digits




– Discover cards: Begin with a 6 and have 16 digits




Card number data should be redacted as in the following examples. Note that 16 digit numbers may or may not be separated into groups of four using hyphens – this is optional. Hyphenation of American Express cards into sections of 4, 6, and 5 digits is similarly common, and also optional. Examples of the expected substitutions for each card type are as follows:




Assignment 2: sed Page 1 of 4

– 5441-4839-9284-3129 → MC-3129




– 3770-123456-78900 → AMEX-8900




– 6093-2033-0662-5389 → DISC-5389




– 4291723799801302 → VISA-1302







Texas Vehicle License Plate numbers should be similarly obliterated. Texas vehicle plates appear in one of two formats, but both will be written with the letters TX and an optional space preceding them. The first type is six alphanumeric characters, optionally separated by a hyphen in the middle. The second type begins with three alphabetic characters, followed by four digits, again optionally separated by a hyphen. Examples of valid type one Texas license plate numbers are:



– TX 32P9ZP




– TX 32P-9ZP




– TX32P9ZP




– TX32P-9ZP







Examples of valid type two Texas license plate numbers are:




– TX JTK8791




– TX JTK-8791




– TXJTK8791




– TXJTK-8791







These numbers should be redacted by simply replacing the license plate number with a sequence of six X characters.




Current Date Placeholder The document authors may use the shorthand symbol <date in order to insert the current date (i.e., today’s date). Regardless of the date on which your script is run, this placeholder should be updated with the correct current date.



Municipality Name Placeholder The authors of these documents may use the shorthand symbol <orgname in order to designate the full name of their municipality. Any such references should be replaced with the full name: City of Gainsville, Florida.



Example




Original redactme.txt:







<orgname



Date : <d a t e



T i t l e : Memorandum #139



4







Assignment 2: sed Page 2 of 4


5
Dear s t a f f :














6




















7
Memorandum #139
h a s been amended
a s
f o l l o w s , i n
a c c o r d a n c e
w i t h
t h e
8
u p d a t e d
e m p l o y e e
o p e r a t i o n s and
p u r c h a s i n g p o l i c y ∗ :




9




















10
The
o n l y
e m p l o y e e s a u t h o r i z e d t o
o p e r a t e
v e h i c l e
#102 ( l i c e n s e
p l a t e
11
TX
JTK8791 ) , v e h i c l e #162 ( l i c e n s e
p l a t e
TX 32P−9ZP) , and
v e h i c l e #262
12
( l i c e n s e
p l a t e TX AJC−6244) a r e
t h o s e e m p l o y e e s
who p o s s e s s t h e
f o l l o w i n g
13
d r i v e r ' s l i c e n s e s :












14


























TXDL 02851332



TXDL 00748892



VADL 590401



FLDL 104281332



 



20
F u r t h e r , u s a g e o f c i t y c r e d i t
c a r d s w i l l be s t r i c t l y l i m i t e d t o t h e
21
f o l l o w i n g d e p a r t m e n t a l c a r d s ,
u n t i l f u r t h e r n o t i c e :
22







5441−4839−9284−3129



3770−123456−78900



6093−2033−0662−5389



4291723799801302



27




Thank you ,



Mgmt



 



31 ∗ P o l i c y r e v i s i o n d a t e 2/1/13 ( o r i g i n a l l y p a s s e d 7 / 1 3 / 9 2 ) .










Redacted Version of redactme.txt:







1 C i t y o f G a i n s v i l l e , F l o r i d a




Date : 09/19/2019



T i t l e : Memorandum #139



4




5
Dear s t a f f :












6
















7
Memorandum #139 h a s
been amended
a s f o l l o w s ,
i n a c c o r d a n c e
w i t h
t h e
8
u p d a t e d
e m p l o y e e o p e r a t i o n s and p u r c h a s i n g p o l i c y ∗ :




9
















10
The o n l y
e m p l o y e e s
a u t h o r i z e d t o
o p e r a t e
v e h i c l e #102 ( l i c e n s e
p l a t e
11
TX XXXXXX) , v e h i c l e
#162 ( l i c e n s e
p l a t e
TX XXXXXX) , and v e h i c l e
#262
12
( l i c e n s e
p l a t e TX XXXXXX) a r e t h o s e e m p l o y e e s
who p o s s e s s
t h e f o l l o w i n g
13
d r i v e r ' s l i c e n s e s :












14



















TXDL XXXXXX



TXDL XXXXXX



VADL XXXXXX



FLDL XXXXXX



 



20
F u r t h e r , u s a g e o f c i t y c r e d i t
c a r d s w i l l be s t r i c t l y l i m i t e d t o t h e
21
f o l l o w i n g d e p a r t m e n t a l c a r d s ,
u n t i l f u r t h e r n o t i c e :
22







MC−3129



AMEX−8900



DISC−5389



Assignment 2: sed Page 3 of 4
VISA−1302



 



Thank you ,






Mgmt



 



31 ∗ P o l i c y r e v i s i o n d a t e 2/1/13 ( o r i g i n a l l y p a s s e d 7 / 1 3 / 9 2 ) .
















Script Execution







Your program should be invoked through a single bash file (see below) with the filename(s) containing the sensitive data as argument(s).




Example: $ assign2.bash redactme.txt







Assignment Data







A sample input file can be found in:




/usr/local/courses/ssilvestro/cs3423/Fall19/assign2.




When using this data, remember that your will be made to overwrite the files. Be sure to make a backup of the files and restore them every time you run the script.




Script Files







Your program should consist of exactly two files:




assign2.bash - the main file which is initially invoked



Exactly one .sed file which is used for a sed invocation run in assign2.bash.






Verifying Your Program







Your program must work for arbitrary files by applying the rules above. You can test your program with the input provided in redactme.txt and compare the output with redacted.txt using diff (check the man-pages on how to use it). You should create your own test cases to test for the recursion feature.







Submission







Turn your assignment in via Blackboard. Your zip file, named abc123.zip (with your abc123) should contain only your bash and sed files.










Assignment 2: sed Page 4 of 4