README.md

Chapter 4: Working with Unix

4.1.2 Exercises

1. Use man to look up the flag for human-readable output from ls.

   $ man ls

   And in the man page search:

   /human-readable
   

2. Get help with man by typing man man into the console.

   $ man man

3. Wouldn't it be nice if there was a calendar command? Use apropos to look for such a command, then use man to read about how that command works.

   $ apropos calendar
   
   $ man calendar

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4.2.2 Exercises

1. Before I organized the photos by year, what command would have listed all of the photos of type .png?

   $ ls *.png

2. Before I organized the photos by year, what command would have deleted all of my hiking photos?

   $ rm *hiking*

3. What series of commands would you use in order to put my figures for a data science course and the pictures I took in the lab into their own folders?

   $ mv *datasci* data_science_course/
   
   $ mv *lab* lab/

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4.3.7 Exercises

1. Search states.txt and canada.txt for lines that contain the word "New".

   $ grep "New" states.txt canada.txt

2. Make five text files containing the names of states that don't contain one of each of the five vowels.

   $ egrep -v "a" states.txt >> states_no_a.txt
   
   $ egrep -v "e" states.txt >> states_no_e.txt
   
   $ egrep -v "i" states.txt >> states_no_i.txt
   
   $ egrep -v "o" states.txt >> states_no_o.txt
   
   $ egrep -v "u" states.txt >> states_no_u.txt

3. Download the GitHub repository for this book and find out how many .html files it contains

   $ git clone https://github.com/seankross/the-unix-workbench
   
   $ cd the-unix-workbench
   
   $ find . -name "*.html" | wc -l

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4.6.2 Exercises

1. Use pipes to figure out how many US states contain the word "New."

   $ grep "New\." states.txt | wc -l

2. Examine your ~/.bash_history to try to figure out how many unique commands you've ever used. (You may need to look up how to use the uniq and sort commands).

   $ cat ~/.bash_history | sort | uniq | wc -l