shell_Day07

function:

Function Description function

　　To avoid duplication of code used, we generally by the function block write, a block of code which is used to implement certain functions, this feature later in the code, the call will be repeated;

Function syntax

　　{check_cpu function
　　　　CAT / proc / cpuinfo
　　}
　　LS / etc /
　　check_cpu [not call function, the body of the function commands are not executed; where to invoke the function execution command body] where

 

　　fun_name () {
　　　　function body
　　　　$ 2 ... $ 10 $. 1
　　}
　　fun_name 2. 3. 1
　　: WQ
　　function.sh. 4. 5. 6. 7. 9 10. 8 12 is 13 is 14. 11 

 

 Function return value

　　return

　　When the function is specified in the judgment statement, we default to return a wrong result, but recently a command indeed correct, this time, we need to return the one we need error status code by return;
　　end of the function, we need specify a return return code is correct; if used in a loop statement, return will be out of the loop;

Function accepts parameters

　　Function variables
　　and common commands, like
　　just need to pay attention to, when the function accepts parameters, does not use an external mass participation, but to prevail within the parameters of the script,
 

Function variables

　　Local variable
　　　　local variable name = xxx
　　　　local variables inside this function takes effect only on
　　local variables
　　　　variables inside the script
　　environment variables
　　　　to take effect in the entire bash Linux system

 

Script Execution

　　bash way to perform - # / bin / bash!
　　　　variable bash script executed as defined in the sub-shell of the current shell;
　　　　the full path or relative path way to perform; - shall be authorized to execute permissions;
　　Source script file or a script file
　　　　when the source of the script is performed in this manner, the value of the internal variable defined in the current of the shell;