Shell Script Best Practices: 1.Constant variables or environment variables name should be UPPER-CASE 2. Changeable variables name should be lower-case 3. Variables in function should be named “_xxx_xx”, starting with underscore “_” to avoid conflict with global variables 4. Use ${xxx} to reference variable, don’t omit {} 5. Code Indent 6. Shell function Treat shell function as real function, and avoid to use global variables Try to put similar functions into a file, and write the test script to do function test Use return/echo to return integer from function, use echo to return string from function and use exit if you want the program to abort The function name should be end with “_func” 7. Comments File header comments should contain description, usage[optional], author, create/change date Line comments – leading line commends or end line comments Sections comments: comments for a block code just like line comments Function comments: should contain des...