Chapter 2 Assignment

The aim of this week’s exercises is to get your shell environments customized and have you practice a little bit of scripting and debugging.

You will modify this file with your answers and submit your assignment in an email to xix2007@med.cornell.edu. The file should be saved as {first}-{last}-assignment{#}.md, and your email should be titled datascibasics assignment {#}.

Follow chapter 2’s exercise module steps and answer the following questions:

Part 1: Dotfiles

Q1:

While creating aliases for your most used commands, you used the awk program and one of its built-in functions substr. Try running the history | awk '{$1="";print substr($0,2)}' | sort | uniq -c | sort -n | tail -n 10 command step by step (add on the pipes | one by one), and explain in your own words, how did your command history change with each piped (|) step?

Q2:

After completing your dotfiles directory, and testing that your installation script works for all your dotfiles, use the tree program to show the contents of your dotfiles directory.

The tree program does not come attached to Linux or macOS distributions, so you can install it quickly with sudo apt-get install tree on Linux or brew install tree on macOS.

Read up on what tree does with tree --help, man tree, or tldr tree (remember to install tldr). Use tree to display the contents of your dotfiles directory with the size of all files attached in human readable format, copy and paste the output tree structure here:

# Your dotfile directory tree structure here

Q3:

Now instead of tree, follow Part 2 step 1, print the ls command you used and its outputs for the dotfile directory here:

# Your command and output here

Part 2: Shell Scripting

Q4:

Write your working marco and polo bash functions here:

# Your functions here

Q5:

Report the following from the debugging script from Part 2 Question 3:

# Your debugging script:

# The standard output stream:

# The output error stream:

# (BONUS) How many runs did it take for the script to fail?

Part 3: Job Control

Q6:

Without using the pid of your sleep 10000 job, how did you kill your job?

# Your command here

Q7:

How did you use the wait command to wait until the sleep process finished before executing ls?

# Your command here

Q8:

Write your working pidwait function here:

# Your pidwait function here