Topic 15

Techniques and syntax of a scripting language used in the IT industry

Bash:

Bash is a command line shell and scripting language developed in 1989 as part of the GNU Project.

Bash was developed as an enhanced version of the original Bourne Shell.

Bash files are saved with the ‘.sh’ extension.

Bash has the following techniques:

• Command history
• Tab expansion
• One dimensional arrays
• Restricted mode
• Arithmetic calculations
• Shell Customisation
• Directory manipulation
• Command Aliases

Bash has the following syntax:

• ‘#’ symbol is used for commenting the code
• The ‘chmod’ command is used to set the execution permission for bash files
• The ‘chown’ command is used to set the ownership for bash files
• The ‘read’ command is used for getting input from the user
• With variables:
  • Variables are not restricted by datatypes. Any type of value can be assigned to variables
  • Must use the ‘$’ in front of the variable name when accessing and displaying it.
  • The name of the variable can only have letters, numbers and an underscore character.
  • The name of the variable can’t start with a number
  • The name of the variable can’t contain any spaces
  • The name of the variable can’t contain special characters except for the underscore
  • There must be no space between the ‘=’ sign when assigning a value to the variable
• With IF statements:
  • Square brackets ‘[ ]’ are used for checking the condition
  • There must be a space between the square brackets ‘[ ]’
  • The ‘then’ keyword is used to begin the IF statement
  • The ‘fi’ keyword is used to end the IF statement
• With WHILE loop:
  • Square brackets ‘[ ]’ are used for checking the condition
  • There must be a space between the square brackets ‘[ ]’
  • The ‘then’ keyword is used to begin the WHILE loop
  • The ‘fi’ keyword is used to end the WHILE loop
• With FOR loop:
  • Square brackets ‘[ ]’ are used for checking the condition
  • There must be a space between the square brackets ‘[ ]’
  • The ‘do’ keyword is used to begin the FOR loop
  • The ‘done’ keyword is used to end the FOR loop

Windows PowerShell:

Windows PowerShell is a command line shell and scripting language developed by Microsoft in 2006.

Windows PowerShell files are saved with the ‘.ps1’ extension.

Windows PowerShell has the following techniques:

• Desired State Configuration
• Error-Handling
• PowerShell Remoting
• Script Debugging
• Tab Expansion
• Network File Transfer
• Constrained Runspaces
• External modules for additional coding functionality

Windows PowerShell has the following syntax:

• ‘#’ symbol is used for commenting the code
• The ‘Set-ExecutionPolicy RemoteSigned’ command is used to set the execution permission for Windows PowerShell files.
• The ‘Read-Host’ command is used to get input from the user.
• With variables:
  • Variables are not restricted by datatypes. Any type of value can be assigned to variables
  • Must use the ‘$’ in front of the variable name when creating, accessing and displaying it.
  • The name of the variable can only have letters, numbers and an underscore character.
  • The name of the variable can’t start with a number
  • The name of the variable can’t contain any spaces
  • The name of the variable can’t contain special characters except for the underscore
  • There must be a space between the ‘=’ sign when assigning a value to the variable
• With IF statements:
  • Round brackets ‘( )’ are used for checking the condition
  • The ‘{’ curly bracket is used to begin the IF statement
  • The ‘}’ curly bracket is used to end the IF statement
    • With WHILE loop:
      • Round brackets ‘( )’ are used for checking the condition
      • The ‘{’ curly bracket is used to begin the WHILE loop
      • The ‘}’ curly bracket is used to end the WHILE loop
    • With FOR loop:
      • Round brackets ‘( )’ are used for checking the condition
      • The ‘{’ curly bracket is used to begin the FOR loop
      • The ‘}’ curly bracket is used to end the FOR loop

    Python:

    Python is a programming language developed by Guido van Rossum in 1991.

    Python files are saved with the ‘.py’ extension.

    Python has the following techniques: ul>

  • Object-oriented
  • GUI support
  • Portability
  • Language Integration
  • Database Connectivity
  • External modules for additional coding functionality

  Python has the following syntax:

  • ‘#’ symbol is used for commenting the code
  • Setting execution permission is not required for Python files.
  • The ‘input()’ function is used to get input from the user.
  • With variables:
    • Variables are not restricted by datatypes. Any type of value can be assigned to variables
    • The name of the variable can only have letters, numbers and an underscore character.
    • The name of the variable can’t start with a number
    • The name of the variable can’t contain any spaces
    • The name of the variable can’t contain special characters except for the underscore
    • There can be a space between the ‘=’ sign, if preferred, when assigning a value to the variable
  • With IF statements:
    • No brackets required for checking the condition
    • Indentation is used to begin and end the IF statement
  • With WHILE loop:
    • No brackets required for checking the condition
    • Indentation is used to begin and end the WHILE loop
  • With FOR loop:
    • No brackets required for checking the condition
    • Indentation is used to begin and end the FOR loop

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