For the file animals.txt from the previous exercise, consider the following command:
$ cut -d , -f 2 animals.txt
The cut command is used to remove or ‘cut out’ certain sections of each line in the file, and cut expects the lines to be separated into columns by a Tab character. A character used in this way is a called a delimiter. In the example above we use the -d option to specify the comma as our delimiter character. We have also used the -f option to specify that we want to extract the second field (column). This gives the following output:
deer
rabbit
raccoon
rabbit
deer
fox
rabbit
bear
The uniq command filters out adjacent matching lines in a file. How could you extend this pipeline (using uniq and another command) to find out what animals the file contains (without any duplicates in their names)?
$ cut -d , -f 2 animals.txt | sort | uniq