Objectives

Command Line Interface Basics

1. Given a folder structure diagram, a list of ‘cd (path)’ commands and target files, match the paths to the target files.

• You can check your PWD, and then reference the tree to cd or cd .. in and out to your desired location.

2. Create, rename, and move folders using unix command line tools.

• Mkdir (make a folder)
• MV (can rename or move folder)

3. Use grep and | to count matches of a pattern in a sample text file and save result to another file.

• Grep -c ‘pattern’ infile.txt > countResults.txt
  • -c : returns count of hits.
  • single arrow: overwrites or creates text file.
• grep ‘pattern’ infile.text | wc -l > countresults.txt

4. Find what -c, -r, and -b flags do in grep by reading the manual.

• -c : count, numbers of matches
• -r : recursive, search entire content of any directory.
• -b : byte-offset, will tell you line number and popsition of grep’s matches.

5. Identify the difference in two different files using diff.

• diff -u file1 file2
  • -u flag used to output a unified diff output.

6. Open and close nano with and without saving a file.

• nano [name of file]

7. Use ‘curl’ to download a file.

• curl -o [url]
  • -o flag actually saves the file and gives us the option of changing the dl’d file name.

8. Read the variables of $PATH.

• echo $PATH
  • reads the current variable of path.

9. Explain the difference between .bash_profile and .bashrc.

• CANCELLED QUESTION

10. Create a new alias by editing the .bash_profile.

• alias berber = ‘ls -al’

11. Given a list of common scenarios, identify when it is appropriate and safe to use sudo, and when it is a dangerous mistake.

• Safe
  • ls commands
  • installing packages
• Dangerous
  • Anything with rm is potentially dangerous

12. Write a shell script that greets a user by their $USER name using echo.

#!/bin/sh
USR = "whoami"
echo "Hello" $USR

13. Use chmod to make a shell script executable.

• chmod +x script name