Having the following bash script:
#!/bin/bash
set -e
function foo() {
# commands that might fails and I want to exit my script
...
echo "result I need as output"
}
my_var=$(foo)
echo "I don't want this if there is an error inside foo"
Using set -e (in bash 4.4.19) does not seem to work with subshells i.e. the last echo command is still being executed). How can I write the code to make the script exit if any of the commands inside foo terminate with non-zero exit code.
I am using bash GNU bash, version 4.4.19(1)-release (x86_64-apple-darwin16.7.0) and the result of calling my script is (where the dots are replaced with an invalid command head -this:
$ ./my_script
head: illegal option -- t
usage: head [-n lines | -c bytes] [file ...]
I don't want this if there is an error inside foo
the exit status of a pipeline command is the exit status of the last command, this can be changed using set -o pipefail, so that pipeline exit status will be <>0 is any command exit status is <>0.
as you used the -e option it is sufficient that the function returns a non 0 exit code for example return 1
in a more general case (without set -e), it can be better to use an explicit exit
my_var=$(foo) || exit 1
can be sufficient because error could be written on standard error (inherited) by subshell.
otherwise reading carefully manual can explain why it doesn't work as you expected
set -e
Exit immediately if [...] returns a non-zero status. The shell does not exit if the command that fails is part of the command list immediately following a while or until keyword, part of the test in an if statement, part of any command executed in a && or || list except the command following the final && or ||, [...].
This option applies to the shell environment and each subshell environment separately (see Command Execution Environment), and may cause subshells to exit before executing all the commands in the subshell.
[...]
And from Command Execution Environment
Subshells spawned to execute command substitutions inherit the value of the -e option from the parent shell. When not in POSIX mode, Bash clears the -e option in such subshells.