Shell script return, ECHO, printf

Ehco and return

return   Returned is the status code, function end Return does not return function return value You can return the function return value with echo in front, return the specified function exit status code

Echo returns the function return value, the function exit status code is the exit status code of the last command of the function

test1.sh

#!/bin/bash     function test () {     echo 200                                                                        }       ret=$ (test) echo  "####$?" echo  "*********** $ret" 

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T est2.sh

#!/bin/bash     function test () {     return 200                                                                     }        ret=$ (test) echo  "####$?" echo  "*********** $ret" 

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In the case of bash, the return command can only be used in a function, not directly in the script

The built-in command return is used for returning from the function, ..., the return command is not required in the function, and when the function is called, the command inside the function is returned to the place where it was called (typically, it is returned to the main program). If a function has a return command, it returns when it executes to return. If return is not the last command in the function, then the other commands after return are no longer executed.

Ehco and printf

Common commands for terminal printing are two types of echo and printf

1, echo Hello Word!

This method cannot print a semicolon because the semicolon is used as a command qualifier in the Shell to mark the end of a command.

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2. Echo ' Hello Word! '

Single quotation marks are printed in a way that does not print variables.

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3. Echo "Hello World"

The exclamation mark cannot be printed directly in double quotation marks, and set +h must be added.

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Echo's Parameters

-E: Identify escape sequences in output content

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-N: Ignore trailing line breaks

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For printf, the two points to be stated are

The default output for 1.printf does not wrap, and the line break needs to add "\ n" Yourself

2.PRINTF supports formatted output

Finish

This article from "Zero Egg" blog, declined reprint!

Shell script return, ECHO, printf