Log in to users3.cs.umb.edu

• Run the ssh client
  
  Connect to users3.cs.umb.edu.

Directory for this Exercise

• Make sure you are in your home directory
  

      cd

• Go to your it244 directory

      cd  it244

• Go to your ex directory
  

      cd  ex

• Create an ex5 directory
  

      mkdir  ex5

• Go to your ex5 directory
  

      cd  ex5

Working with Pagers

• Use cat on the syllabus page from the class web site

      cat  /home/tsoro/public_html/teaching/IT244_html/syllabus_it244.html

  Scroll back up in your terminal session to see the beginning of the file.
  
  
• Use more on the same file

      more  /home/tsoro/public_html/teaching/IT244_html/syllabus_it244.html

• Move down one screen

      Space

• Look at the more help section

      h

• Exit the help section
  

  Control L

• Use the Enter key to moves down a few lines

      Enter
      Enter
      Enter

• Move to the end of the file
  
  Hit Space as many times as you need to.
  
  You should reach the end of the file and exit more.
  
• Use less on the same file

      less  /home/tsoro/public_html/teaching/IT244_html/syllabus_it244.html

• Look at the less help section
  

  h

• Exit the help section
  

  q

• Move to the end of the file
  
  Hit Space until you reach the end of the file.
  
  You see (END) but you are still in less.
  
• Quit less

      q

Filename Completion

• Create the directory test

      mkdir  test

• Move to the test directory

      cd  test

• Create some files

      touch  foo  foobar  foobletch  bletch

• Look at the contents of the directory
  

      ls

• Use filename complete to run ls on bletch

      ls  ble[Tab][Enter]

  [Tab] and [Enter] are not words you type on the command line.
  
  [Tab] means hit the Tab key and [Enter] means hit the Enter key.
  
• Use filename completion to see all files with "foo" in the name

      ls  foo[Tab][Tab]

  After the first Tab, you should hear a beep. After the second, all files beginning with "foo" should be displayed.
  
• Keep typing to run ls on foobletch

      ls foobl[Tab][Enter]

  As you supply more letters in the filename, the completion mechanism narrows down the possibilities.
  

Experimenting with echo

• Run echo with a string argument

      echo  foo  bar  bletch

• Use echo to display a system variable

      echo  SHELL:  $SHELL

• You must use a $ when displaying the value of a variable

      echo SHELL:  SHELL

hostname

• Determine the name of your current host

      hostname

• Determine the IP address of your current host

      hostname  -i

grep

• Go to the it244_files directory
  

      cd   /home/tsoro/course_files/it244_files

• Look at the contents of foo.txt
  

      cat  foo.txt

• Look for lines with the string "foo" in foo.txt
  

      grep  foo  foo.txt

• Experiment with the -i option
  
  First look for "bar" without the -i option

      grep  bar  foo.txt

  Now try the same search with -i

      grep  -i  bar  foo.txt

  Notice that grep now prints a new line with the word "Bar" in it.
  
  
• Use grep with the -r option
  
  grep, when used with the -r option, looks in all subdirectories of the directory given to it as its second argument

      grep  -r  foo  .

  The . means the current directory.
  
  Everything up to the colon, : , is the path to the file in which the string was found.
  
  The text after the colon is the line itself.
  
  The entries in the directory .svn are associated with the versioning software, supathersion, I use in all my work.
  
  
• Use grep -v to remove unwanted lines
  
  Many of the lines returned in the previous invocation of grep come from files with the string "svn" in their file names.
  
  These are files created by subversion.
  
  Let's remove these lines grep twice, using a pipe, |, to feed the output of the first invocation of grep into the input of the second

      grep  -r  foo  .  |  grep  -v  svn

  Notice that all the entries in the subversion files have been removed.
  
  We'll discuss pipes in a future class.

head

• Display the contents of red_sox.txt

      cat  red_sox.txt

• Display the first 10 lines of red_sox.txt

      head  red_sox.txt

• Display the first line of red_sox.txt

      head  -1  red_sox.txt

tail

• Display the last 10 lines of red_sox.txt

      tail  red_sox.txt

• Display the last two lines of red_sox.txt

      tail  -2 red_sox.txt

sort

• Look at fruit.txt

      cat  fruit.txt

• Run sort on this file

      sort  fruit.txt

• Sort this file in reverse alphabetical order

      sort  -r  fruit.txt

• Look at numbers.txt

      cat  numbers.txt

• Run sort on this file without any options

      sort  numbers.txt

  Since the numbers from 10 to 19 begin with a 1 they appear before 2
  
  
• Sort numbers.txt in numerical order

      sort  -n  numbers.txt

• Sort numbers.txt in reverse numerical order

      sort  -nr  numbers.txt

  Note that sort allows you to combine options after the dash.
  
  
  
  
  

Create a Bash script

• Go to your home directory
  

      cd

• Go to your it244 directory
  

      cd  it244

• Go to your ex directory
  

      cd  ex

• Go to your ex5 directory
  

      cd  ex5

• Create the script file ex5.sh
  

      nano  ex5.sh

• Write into this file commands from certain of the sections above
  
  Go back to the section of this Class Exercise called Experimenting with echo.
  
  Enter all the commands from the Experimenting with echo section up to and including the section called sort into this script file.
  
  Do not run the more or less commands inside ex5.sh
  
  Do not use Tab completion inside ex5.sh
  
  You do not have to write echo Step commands in scripts for the Class Exercise.
  
  
• Save and quit
  
  
  
• Test you script
  

  	~tsoro/it244_test/ex05.sh

  When the script asks if you are ready for more, hit Return or Enter.
  
  
• Let me check work script