Post by Chunxi Zhang
My experience
In general, I think this exercise is not hard. It is because we praticed some of this assignment erlier in the class. From this assignment, I have learned some new founctions of command line. I used to think it is not very useful. It took me sometime to finish the No.5 question. Then I realized I need to create a pipeline to see what animals are in the file, then we need to sort and unique the outputs.
Challenge
1.
The sort command will alphabetizes the file by the first integer. However, sort -n will sort the outputs by the numbers
instead of chatacter.
2.
wc -l < mydata.dat the program will send the input of mydata.dat to wc -l's standard input
wc -l mydata.dat the program will open mydata.dat and get the output results
3.
uniq is very useful expecially for large scale data set. It removes only adjacent duplicated lines by comparing line
by line. Therefore it can save space make the data set easier to read.
Other command can be sort salmon.txt| uniq . It can remove all adjacent duplicant lines.
4.
It can be divided into three different steps. Once we get anima.text, we use "head -5" to get the first 5 lines of the test.
2012-11-05,deer
2012-11-05,rabbit
2012-11-05,raccoon
2012-11-06,rabbit
2012-11-06,deer
Then "tail -3" will print the last three lines of the output.
2012-11-05,raccoon
2012-11-06,rabbit
2012-11-06,deer
Finally, "sort -r > final.txt" will resort the outcome and save the result as "final.txt".
2012-11-06,rabbit
2012-11-06,deer
2012-11-05,raccoon
5.
It took me some time to get my head straight. But once you understand what you want, it is easy.
cut -d, -f 2 animals.txt | sort | uniq