return bash script

Return Values When a bash function completes, its return value is the status of the last statement executed in the function, 0 for success and non-zero decimal number in the 1 - 255 range for failure. The return status can be specified by using the return keyword, and it is assigned to the variable $? .

1. How do you return a script?
2. What is return code in shell script?
3. What is $0 $1 in shell script?
4. What is #!/ Bin bash?
5. How does a shell script return a function?
6. How do you exit a bash script?
7. What is Exit 0 and Exit 1 in shell script?
8. What does return code 255 mean?
9. How do I find my bash return code?
10. What is Echo $1?
11. What do the symbol pairs of $# $? $1 $2 and $@ mean in a bash script?
12. How do bash scripts work?

How do you return a script?

The return statement will return to the script from where it was called, while the exit statement will end the entire script from wherever it is encountered. return 0 # Returns to where the function was called. $? contains 0 (success).

What is return code in shell script?

Exit codes are a number between 0 and 255, which is returned by any Unix command when it returns control to its parent process. ... These can be used within a shell script to change the flow of execution depending on the success or failure of commands executed.

What is $0 $1 in shell script?

$1 is the first command-line argument passed to the shell script. Also, know as Positional parameters. ... $0 is the name of the script itself (script.sh) $1 is the first argument (filename1) $2 is the second argument (dir1)

What is #!/ Bin bash?

When you tell #!/bin/bash then you are telling your environment/ os to use bash as a command interpreter. This is hard coded thing. Every system has its own shell which the system will use to execute its own system scripts. This system shell can be vary from OS to OS(most of the time it will be bash.

How does a shell script return a function?

A function may return a value in one of four different ways:

1. Change the state of a variable or variables.
2. Use the exit command to end the shell script.
3. Use the return command to end the function, and return the supplied value to the calling section of the shell script.

How do you exit a bash script?

The exit code of the function (within the function) is set by using return . So when in a function return 0 is run, the function execution terminates, giving an exit code of 0.

What is Exit 0 and Exit 1 in shell script?

exit(0) indicates successful program termination & it is fully portable, While. exit(1) (usually) indicates unsucessful termination. However, it's usage is non-portable. Note that the C standard defines EXIT_SUCCESS and EXIT_FAILURE to return termination status from a C program.

What does return code 255 mean?

The error code "255" usually means that it is not able to find the file you are asking it to execute. ... The Windows events logs show a corresponding Error code 255 is one of those software errors that there is not a documented fix for on the Microsoft sites.

How do I find my bash return code?

To check the exit code we can simply print the $? special variable in bash. This variable will print the exit code of the last run command. As you can see after running the ./tmp.sh command the exit code was 0 which indicates success, even though the touch command failed.

What is Echo $1?

$1 is the argument passed for shell script. then. $1 will be hello. $2 will be 123.

What do the symbol pairs of $# $? $1 $2 and $@ mean in a bash script?

$# Stores the number of command-line arguments that were passed to the shell program. ... "$@" Stores all the arguments that were entered on the command line, individually quoted ("$1" "$2" ...). So basically, $# is a number of arguments given when your script was executed. $* is a string containing all arguments.

How do bash scripts work?

A Bash script is a plain text file which contains a series of commands. These commands are a mixture of commands we would normally type ouselves on the command line (such as ls or cp for example) and commands we could type on the command line but generally wouldn't (you'll discover these over the next few pages).