Let's imagine I have a bash script, where I call this:
bash -c "some_command"
do something with code of some_command here
Is it possible to obtain the code of some_command
? I'm not executing some_command
directly in t开发者_JAVA百科he shell running the script because I don't want to alter it's environment.
$?
will contain the return code of some_command
just as usual.
Of course it might also contain a code from bash, in case something went wrong before your command could even be executed (wrong filename, whatnot).
Here's an illustration of $?
and the parenthesis subshell mentioned by Paggas and Matti:
$ (exit a); echo $?
-bash: exit: a: numeric argument required
255
$ (exit 33); echo $?
33
In the first case, the code is a Bash error and in the second case it's the exit code of exit
.
You can use the $?
variable, check out the bash documentation for this, it stores the exit status of the last command.
Also, you might want to check out the bracket-style command blocks of bash (e.g. comm1 && (comm2 || comm3) && comm4
), they are always executed in a subshell thus not altering the current environment, and are more powerful as well!
EDIT: For instance, when using ()-style blocks as compared to bash -c 'command', you don't have to worry about escaping any argument strings with spaces, or any other special shell syntax. You directly use the shell syntax, it's a normal part of the rest of the code.
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