In this lab, you will try various commands to view and modify file data. All of these commands must be run as an ordinary Linux user, not as root or or by using sudo or su.
cat, more, and less commands to view the contents of /etc/hosts.
cat /etc/hosts
more /etc/hosts
less /etc/hosts
Now try the same commands to view the /etc/services file to see what differences there are when the file being viewed is bigger.
mkdir ~/lab6
find command to list the regular files in your home directory.
find ~ -type f
Find the same files again, but this time show a human-friendly size for each file as well as its pathname by using the exec option to the find command. Use output redirection to save the list of files with their sizes in a file called filesizes.txt in your lab6 directory.
find ~ -type f -exec ls -sh {} + > ~/lab6/filesizes.txt
sort command on the list of files in your filesizes.txt file to sort them by space used and save the sorted list in a file named sortedfilesizes.txt in your lab6 directory.
sort -h ~/lab6/filesizes.txt > ~/lab6/sortedfilesizes.txt
Challenge: Create a single command using pipes to do the find, then the sort, and then send the sorted list to the tail command to only include the 5 largest files in your output list and use output redirection to save that list to a file in your lab6 directory named big5.txt. The file sizes should be human-friendly. Use cat to verify that your big5.txt file has the right results in it.
grep to save a list of lines from /etc/services that have the word SSL in them to a file in your lab6 directory named ssl-services.txt.
grep SSL /etc/services > ~/lab6/ssl-services.txt
Challenge: Use grep to search /etc/services and output only the lines for services whose names end with an s. You will have to research the content of the services (i.e. man 5 services) file and the grep command to perform this task. You will also have to create a regular expression pattern to find only the lines with service names that end with an s. This one is not easy!
nano or vi(vim) to add several kinds of food (keep the food names to single words for simplicity) to your lab6/foods.txt file. For each line in the file, add a word to the end of the line specifying one example of what would eat the food on that line (e.g. fly spider). Be sure to keep the original foods in the file and put the word cat as the eater of those things (i.e. mouse cat). Use the sort command twice; first to show the file sorted by food name, then by what would eat it.
cp ~/lab5/txts/food.txt ~/lab6/foods.txt
nano ~/lab6/foods.txt
sort ~/lab6/foods.txt
sort -k 2 ~/lab6/foods.txt
sed to display your lab6/foods.txt file, substituting the word kitty for the word cat wherever you have it in your foods.txt file. Do not modify your foods.txt file, only display the changed version. Then run your sed command again, this time redirecting the output to a file named kittyfoods.txt in your lab6 directory.
sed s/cat/kitty/g ~/lab6/foods.txt
sed s/cat/kitty/g ~/lab6/foods.txt > ~/lab6/kittyfoods.txt
diff and cmp to compare your foods.txt file to your kittyfoods.txt file.
diff ~/lab6/foods.txt ~/lab6/kittyfoods.txt
cmp ~/lab6/foods.txt ~/lab6/kittyfoods.txt
Capture screenshots of the terminal window showing your prompt, commands, and as much of the output for each command as fits in the window with your command still showing. Submit a single PDF file to blackboard containing your screenshots in the order they were performed, along wityh your responses to the questios asked in the lab.