Programming Exercise A for RWET

exercise_a.txt

RWET Programming Exercise A
Text processing on the UNIX command line

---
Step 1. Write the command to download the text file with the following URL to
your computer with the filename "frost.txt". (Hint: You'll need to use the
"curl" command, and possibly redirection with ">").
 
Here's the URL:
  http://rwet.decontextualize.com/texts/frost.txt
 
Write the command here:

$ curl http://rwet.decontextualize.com/texts/frost.txt > frost.txt

(This command will print no output to the screen.)

---
Step 1a. Verify step 1 by typing the following command:

$ cat <frost.txt

You should see the following:

  Two roads diverged in a yellow wood,
  And sorry I could not travel both
  And be one traveler, long I stood
  And looked down one as far as I could
  To where it bent in the undergrowth;

  Then took the other, as just as fair,
  And having perhaps the better claim,
  Because it was grassy and wanted wear;
  Though as for that the passing there
  Had worn them really about the same,

  And both that morning equally lay
  In leaves no step had trodden black.
  Oh, I kept the first for another day!
  Yet knowing how way leads on to way,
  I doubted if I should ever come back.

  I shall be telling this with a sigh
  Somewhere ages and ages hence:
  Two roads diverged in a wood, and I—
  I took the one less travelled by,
  And that has made all the difference.

---
Step 2. Write a command that displays the only the lines from frost.txt
that contain the string "And".

$ cat < frost.txt | grep 'And'

You should see the following:

  And sorry I could not travel both
  And be one traveler, long I stood
  And looked down one as far as I could
  And having perhaps the better claim,
  And both that morning equally lay
  And that has made all the difference.

---
Step 3. Using a pipe, write a command that extracts the second word from
each of the lines you displayed in Step 3. (Hint: Use the "cut" command.)

$ cat < frost.txt | grep 'And' | cut -d' ' -f2

You should see the following:

  sorry
  be
  looked
  having
  both
  that

---
Step 4. Add one more element to the pipe in step 3, so that the words are
displayed in alphabetical order.

$ cat < frost.txt | grep 'And' | cut -d' ' -f2 | sort

You should see the following:

  be
  both
  having
  looked
  sorry
  that

---
Step 5. We didn't talk about "fold" in class, but it's a useful command for
word-wrapping text. Investigate the "fold" command with "man" (type "man fold")
and write a command below to word-wrap "frost.txt" at 20 characters, keeping
word boundaries intact.

$ cat < frost.txt | fold -w 20 -s


Your output should look like this:

  Two roads diverged 
  in a yellow wood,
  And sorry I could 
  not travel both
  And be one 
  traveler, long I 
  stood
  And looked down one 
  as far as I could
  To where it bent in 
  the undergrowth;
  
  Then took the 
  other, as just as 
  fair,
  And having perhaps 
  the better claim,
  Because it was 
  grassy and wanted 
  wear;
  Though as for that 
  the passing there
  Had worn them 
  really about the 
  same,
  
  And both that 
  morning equally lay
  In leaves no step 
  had trodden black.
  Oh, I kept the 
  first for another 
  day!
  Yet knowing how way 
  leads on to way,
  I doubted if I 
  should ever come 
  back.
  
  I shall be telling 
  this with a sigh
  Somewhere ages and 
  ages hence:
  Two roads diverged 
  in a wood, and I—
  I took the one less 
  travelled by,
  And that has made 
  all the difference.