How do I return a Unix code?
How do I return a Unix code?
Exit codes are a number between 0 and 255, which is returned by any Unix command when it returns control to its parent process. Other numbers can be used, but these are treated modulo 256, so exit -10 is equivalent to exit 246 , and exit 257 is equivalent to exit 1 .
What is return code in shell script?
What is an exit code in the UNIX or Linux shell? An exit code, or sometimes known as a return code, is the code returned to a parent process by an executable. On POSIX systems the standard exit code is 0 for success and any number from 1 to 255 for anything else.
What is $# in Unix?
$# is the number of arguments, but remember it will be different in a function. $# is the number of positional parameters passed to the script, shell, or shell function. This is because, while a shell function is running, the positional parameters are temporarily replaced with the arguments to the function.
What does return code 2 mean?
invalid usage
Exit code 2 signifies invalid usage of some shell built-in command. Examples of built-in commands include alias, echo, and printf.
What does $! Mean in bash?
Actually, these variables were inherited by bash from the Bourne shell. $$ means current PID. $! is the PID of the last program your shell ran in the background (e.g. myprog & )
What is $1 in Linux?
$1 is the first command-line argument passed to the shell script. $0 is the name of the script itself (script.sh) $1 is the first argument (filename1) $2 is the second argument (dir1)
How do I find my 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.
What does exit code 99 mean in Linux?
There is no significance to exiting with code 99, other than there is perhaps in the context of a specific program. Either way, exit exits the shell with a certain exit code, in this case, 99. You can find more information in help exit: exit: exit [n] Exit the shell.
How to exit the shell with a certain exit code?
Either way, exit exits the shell with a certain exit code, in this case, 99. You can find more information in help exit: exit: exit [n] Exit the shell. Exits the shell with a status of N. If N is omitted, the exit status is that of the last command executed.
What is the return code of a subshell in Linux?
The return code of the subshell is the return code of the final command (command3 in this example). That return code will affect the overall command. So the output of this script: cp /foo /bar && ( echo Success ; echo Success part II; /bin/false ) || ( echo Failed ; echo Failed part II )
What does it mean when a shell script returns 0?
The shell will get a 0 as the return code. This zero means everything was OK. However, if your program has found some error condition, you should exit with a non-zero return code, to inform the shell that something has gone wrong.
