Corning Community College
CSCS1730 UNIX/Linux Fundamentals
~~TOC~~
To create a script that can, with information provided by the user, display useful reference data.
We've encountered many things in our UNIX journey so far, and have been readily building upon past experiences as we achieve newer and better successes. Of particular focus, we've been looking at shell scripting, and that will be the primary focus of this week's project.
There are collections of information quite useful to anyone journeying in a discipline, and computing is no different. We often encounter information represented in certain units more than others, or various quantities, or even particular number bases.
One particular collection of information involves that of binary, octal, decimal (in signed and unsigned capacities) and hexadecimal numbers. We may encounter a tool that gives us information in octal and we need to feed it into another tool as binary or decimal; these sorts of transactions are common and crop up time and time again.
Having a strong handle on this information is vital for on-going success in the computing field.
As such, it is important to have close at hand the knowledge of the following number bases:
While we don't need to have hundreds of values memorized, it IS a good idea to have a rather quick recollection of enough values that can be used for debugging purposes. The first 16 values of each of these is such a preferred range. Not only does it give us a range of information, but for the powers-of-two bases, can actually fit in and be propagated quite nicely with little added effort.
It is your task to write a script that, when run without any arguments, produces the following table of information (and displayed/formatted in this very manner):
lab46:~/src/unix/irt0$ ./irt0 base 2 | base 8 | base10 | base16 ----------+----------+----------+---------- 0000 | 000 | 0 | 0x00 0001 | 001 | 1 | 0x01 0010 | 002 | 2 | 0x02 0011 | 003 | 3 | 0x03 0100 | 004 | 4 | 0x04 0101 | 005 | 5 | 0x05 0110 | 006 | 6 | 0x06 0111 | 007 | 7 | 0x07 1000 | 010 | 8 | 0x08 1001 | 011 | 9 | 0x09 1010 | 012 | 10 | 0x0A 1011 | 013 | 11 | 0x0B 1100 | 014 | 12 | 0x0C 1101 | 015 | 13 | 0x0D 1110 | 016 | 14 | 0x0E 1111 | 017 | 15 | 0x0F lab46:~/src/unix/irt0$
Additionally, your script should take the following arguments (in this order):
Numerical arguments are to be given in decimal.
If provided, they should adjust the script's output accordingly.
Some additional constraints/assumptions you can make:
In the event only the starting value is specified, assume a count of 16 (so display 16 values, starting at the starting value). Note that for binary and octal, all numbers should be displayed in a block, so if an additional place value comes into the picture, leading zeros must be visible on the preceding values.
For example:
lab46:~/src/unix/irt0$ ./irt0 12 base 2 | base 8 | base10 | base16 ----------+----------+----------+---------- 01100 | 014 | 12 | 0x0C 01101 | 015 | 13 | 0x0D 01110 | 016 | 14 | 0x0E 01111 | 017 | 15 | 0x0F 10000 | 020 | 16 | 0x10 10001 | 021 | 17 | 0x11 10010 | 022 | 18 | 0x12 10011 | 023 | 19 | 0x13 10100 | 024 | 20 | 0x14 10101 | 025 | 21 | 0x15 10110 | 026 | 22 | 0x16 10111 | 027 | 23 | 0x17 11000 | 030 | 24 | 0x18 11001 | 031 | 25 | 0x19 11010 | 032 | 26 | 0x1A 11011 | 033 | 27 | 0x1B lab46:~/src/unix/irt0$
We can adjust the range displayed by specifying an ending value as well:
lab46:~/src/unix/irt0$ ./irt0 37 42 base 2 | base 8 | base10 | base16 ----------+----------+----------+---------- 100101 | 045 | 37 | 0x25 100110 | 046 | 38 | 0x26 110001 | 047 | 39 | 0x27 101000 | 050 | 40 | 0x28 101001 | 051 | 41 | 0x29 101010 | 052 | 42 | 0x2A lab46:~/src/unix/irt0$
With a specified starting/ending value pair, we can display as little as 1 value and (theoretically) as many as we want.
With the word “signed” given as the third parameter (ie starting and ending values are required), the following will occur:
lab46:~/src/unix/irt0$ ./irt0 2 14 signed base 2 | base 8 | base10 | signed | base16 ----------+----------+----------+----------+---------- 0010 | 002 | 2 | +2 | 0x02 0011 | 003 | 3 | +3 | 0x03 0100 | 004 | 4 | +4 | 0x04 0101 | 005 | 5 | +5 | 0x05 0110 | 006 | 6 | +6 | 0x06 0111 | 007 | 7 | +7 | 0x07 1000 | 010 | 8 | -8 | 0x08 1001 | 011 | 9 | -7 | 0x09 1010 | 012 | 10 | -6 | 0x0A 1011 | 013 | 11 | -5 | 0x0B 1100 | 014 | 12 | -4 | 0x0C lab46:~/src/unix/irt0$
Signed values are how the computer represents negative numbers. The convention in common use is to reference the most significant bit (the left-most): if it is a 1, it is considered negative, and 0, it is positive.
The actual process of representing a number as a negative value is known as two's complement. In it, we invert the bits and add one.
For instance, if we had 4-bit values and we wanted to display a 1 as a negative value:
0001 <-- value 1110 <-- inversion of value's bits +1 <-- adding 1 ==== 1111 <-- -1
Evaluation will be based on correctness of values as well as on formatting/spacing.
You'll notice that everything lines up and is positioned similarly:
By successfully performing this project, you should have a set of task#.cli files (one for each task). You will want to submit these, along with a upf1steps file.
To submit this project to me using the submit tool, run the following command at your lab46 prompt:
$ submit unix upf1 upf1steps task*.cli Submitting unix project "upf1": -> upf1steps(OK) -> task0.cli(OK) -> task1.cli(OK) -> task2.cli(OK) -> task3.cli(OK) ... SUCCESSFULLY SUBMITTED
You should get some sort of confirmation indicating successful submission if all went according to plan. If not, check for typos and or locational mismatches.
I'll be looking for the following:
78:upf1:final tally of results (78/78) *:upf1:upf1steps submitted via submit tool [2/2] *:upf1:upf1steps covers steps from copy until submit [4/4] *:upf1:upf1steps squelches any STDERR output [4/4] *:upf1:upf1steps only displays required STDOUT output [4/4] *:upf1:task0.cli produces correct result [2/2] *:upf1:task0.cli uses specified input_value [1/1] *:upf1:task0.cli uses specified input_unit [1/1] *:upf1:task0.cli solution in specified output_unit [2/2] *:upf1:task0.cli solution using specified precision [1/1] *:upf1:task0.cli solution using specified delimiter [1/1] *:upf1:task1.cli produces correct result [2/2] *:upf1:task1.cli uses specified input_value [1/1] *:upf1:task1.cli uses specified input_unit [1/1] *:upf1:task1.cli solution in specified output_unit [2/2] *:upf1:task1.cli solution using specified precision [1/1] *:upf1:task1.cli solution using specified delimiter [1/1] *:upf1:task2.cli produces correct result [2/2] *:upf1:task2.cli uses specified input_value [1/1] *:upf1:task2.cli uses specified input_unit [1/1] *:upf1:task2.cli solution in specified output_unit [2/2] *:upf1:task2.cli solution using specified precision [1/1] *:upf1:task2.cli solution using specified delimiter [1/1] *:upf1:task3.cli produces correct result [2/2] *:upf1:task3.cli uses specified input_value [1/1] *:upf1:task3.cli uses specified input_unit [1/1] *:upf1:task3.cli solution in specified output_unit [2/2] *:upf1:task3.cli solution using specified precision [1/1] *:upf1:task3.cli solution using specified delimiter [1/1] *:upf1:task4.cli produces correct result [2/2] *:upf1:task4.cli uses specified input_value [1/1] *:upf1:task4.cli uses specified input_unit [1/1] *:upf1:task4.cli solution in specified output_unit [2/2] *:upf1:task4.cli solution using specified precision [1/1] *:upf1:task4.cli solution using specified delimiter [1/1] *:upf1:task5.cli produces correct result [2/2] *:upf1:task5.cli uses specified input_value [1/1] *:upf1:task5.cli uses specified input_unit [1/1] *:upf1:task5.cli solution in specified output_unit [2/2] *:upf1:task5.cli solution using specified precision [1/1] *:upf1:task5.cli solution using specified delimiter [1/1] *:upf1:task6.cli produces correct result [2/2] *:upf1:task6.cli uses specified input_value [1/1] *:upf1:task6.cli uses specified input_unit [1/1] *:upf1:task6.cli solution in specified output_unit [2/2] *:upf1:task6.cli solution using specified precision [1/1] *:upf1:task6.cli solution using specified delimiter [1/1] *:upf1:task7.cli produces correct result [2/2] *:upf1:task7.cli uses specified input_value [1/1] *:upf1:task7.cli uses specified input_unit [1/1] *:upf1:task7.cli solution in specified output_unit [2/2] *:upf1:task7.cli solution using specified precision [1/1] *:upf1:task7.cli solution using specified delimiter [1/1]