Log in to users3.cs.umb.edu

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

Directory for this Exercise

• Go to your ex directory

      cd  ~/it244/ex

• Create an ex22 directory
  

      mkdir  ex22

• Go to your ex22 directory
  

      cd  ex22

test with Numbers

• Use test with the -eq (equality for numbers) operator
  

      test 4 -eq 5; echo $?

  Since anything other than 0 as an exit status signals failure, this means that the equality test has failed.
• Use the -eq operator with the same number on both sides
  

      test 4 -eq 4; echo $?

  Since 0 means success, this means that the expression evaluated to true.
• Use test with the -ne (not equal for numbers) operator
  

      test 4 -ne 5; echo $?

  0 means true.
• Use -ne again
  

      test 4 -ne 4; echo $?

  1 means false.
• Use test with the -gt (greater than) operator
  

      test 4 -gt 5  ; echo $?
      test 5 -gt 4  ; echo $?

• Use the -ge (greater than or equal to) operator
  

      test 5 -ge 4 ; echo $?
      test 5 -ge 5 ; echo $?

• Use the -lt (less than operator)
  

      test 4 -lt 5 ; echo $?
      test 5 -lt 4 ; echo $?

• Use the -le (less than or equal to) operator
  

      test 4 -le 5 ; echo $?
      test 4 -le 4 ; echo $?

test with String Comparison Operators

• Use test with the = (string equality) comparison operator
  

      test foo = foo ; echo $?
      test foo = bar ; echo $?

• Use test with the != (string not equal) comparison operator
  

      test foo != bar  ; echo $?
      test foo != foo  ; echo $?

test with Single String Operators

• Use test with the -n (length greater than 0) string operator
  

      test -n foo ; echo $?
      test -n "" ; echo $?

• Use test with the -z (length is 0) string operator
  

      test -z "" ; echo $?
      test -z foo ; echo $?

arg_test.sh

• Make sure you are in your ex22 directory
  

      cd ~/it244/ex/ex22

• Using your favorite editor create the script arg_test.sh

• Change the permissions on arg_test.sh to make it executable
  

      chmod 755 arg_test.sh

• Test the script several times
  

      ./arg_test.sh
      ./arg_test.sh foo
      ./arg_test.sh foo bar
      ./arg_test.sh foo bar bletch

• Test you script
  

      ~tsoro/it244_test/ex22.sh

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