A shell function is nothing but a set of one or more commands/statements that act as a complete routine. If the search is unsuccessful, the shell searches for a defined shell function named command_not_found_handle. That means, the original issue I sought out to fix wouldn’t actually be fixed. How to find out the exit code of a command The most common use of the trap command though is to trap the bash-generated psuedo-signal named EXIT. which means exiting in the Bash function, only exits from that shell - which makes sense but I didn’t know that. 0 exit status means the command was successful without any errors. # running above script $ bash helloJohn.sh Hello, John Doe If you don't modify the argument in any way, there is no need to copy it to a local variable - simply echo "Hello, $1" . If [value] is omitted, the return status is that of the last command executed within the function or script. It turns out when you cal a Bash function using the syntax $() you are actually invoking a subshell (duh!) There is a simple, useful idiom to make your bash scripts more robust - ensuring they always perform necessary cleanup operations, even when something unexpected goes wrong. You can use $1 , $2 , $3 and so on to access the arguments inside the function. Articles Related Syntax return [n] If used: inside a If N is not given, the exit status code is that of the last executed command.. ... One can force script to exit with the return value specified by [value]. Executing the exit in a subshell is one pitfall: #!/bin/bash function calc { echo 42; exit 1; } echo $(calc) The script prints 42, exits from the subshell with return code 1, and continues with the script.Even replacing the call by echo $(CALC) || exit 1 does not help because the return code of echo is 0 regardless of the return code of calc.And calc is executed prior to echo. At the beginning of my Linux experience I spent a lot of time dealing with the fallout of premature script exits. When the script exits, the egress function will run. We then call that function in the trap statement. What is an exit code in bash shell? Say, for example, that you have a script that creates a temporary file. If that function exists, it is invoked in a separate execution environment with the original command and the original command’s arguments as its arguments, and the function’s exit status becomes the exit status of that subshell. Rather than deleting it at each place where you exit your script, you just put a trap command at the start of your script that deletes the file on exit: My problem then is exiting from deep within the function call stack. exit 1 or exit 2 etc. Every Linux or Unix command executed by the shell script or user has an exit status. by a signal)). The trap command is a simple and effective way to ensure your bash scripts exit cleanly. A non-zero (1-255 values) exit status means command was a failure. You can exit a script at any place using the keyword exit.You can also specify an exit code in order to indicate to other programs that or how your script failed, e.g. Return is a bash builtin function that causes to update the exit status specified by n. Return is intended to be used only for signaling errors, not for returning the results of function. The secret sauce is a pseudo-signal provided by bash, called EXIT, that you can trap ; commands or functions trapped on it will execute when the script exits for any reason. Exit status is an integer number. The commands' exit status can be used in conditional commands such as if.In the following example grep will exit with zero (which means true in … Let us see how to pass parameters to a Bash function. Hello Okay, for reasons related to sourcing a script from another script, I've had to put my main loop into a function, and from there I call other functions. Examples #. Exit code 0 Success Exit code 1 General errors, Miscellaneous errors, such as "divide by zero" and other impermissible operations Exit code 2 Misuse of shell builtins (according to Bash documentation) Example: empty_function() {} Caveat: Using the proper exit code is not a requirement and is not enforced by the shell. (By convention, exit code 0 is for success and anything greater than 0 signifies failure; however, also by convention, exit codes above 127 are reserved for abnormal termination (e.g. Conclusion. Functions, exit, and kill in bash. When used in shell scripts, the value supplied as an argument to the exit command is returned to the shell as an exit code..