I was reading about traps, but only return works for me in my shell script, so was wondering what status or code it returns, so what I tried is,
#!/bin/bash
seeOutput=`return`
echo $seeOutput
It's just returning a new line and when done on terminal, it says,
-bash: return: can only `return' from a function or sourced script
which I already know :p I just need to know "return"'s exit status.
What you're doing is calling a shell command return which doesn't make sense.
In general, return with no value followed returns the exit status of the last command executed.
From man: Causes a function to exit with the return value specified by n. If n is omitted, the return status is that of the last command executed in the function body.
return code is stored in $? variable.
false ; echo $?
true ; echo $?
would return
1
0
unix convention is that 0 means OK. in your exemple, seeOuput hold whatever output from the back quoted command.
Do not mistake output and return code.
This is how I used it:
f()
{
ls $AAA
return $?
}
g()
{
f
return $?
}
d()
{
g
echo $?
}
AAA=
d
_
<contents of dir>
0
_
AAA=sdsasdasd
d
_
ls: sdsasdasd: No such file or directory
2
returndefaults to true. bash 4.3 has includedreturn -1which means error. Thusreturnaccept negative values as return value (e.g. return -1 will show as (8 bit) 255 in the caller). See wiki.bash-hackers.org/scripting/bashchangesreturndefaults toreturn "$?"(that is, it returns with the exit status of the last run command).returnon its own indicates true as you'd do in creturn 0to indicate success. Anything else will be false and ofcourse based on the status of$?returned from the last command. e.gf(){ args=2; [[ $# = $args ]] && return || return ; }; f 1Will hit the secondreturnwhich will be false. Howeverf(){ args=2; [[ $# = $args ]] && return || return ; }; f 1 2will hit the firstreturnwhich will be true.returnfrom a function or a sourced script, why are you calling it in another context? What do you expect to happen? And what do you mean by “ "return"'s exit status”? Sincereturncauses its context to exit, there's no way to observe any exit status of thereturninstruction itself, what you observe is the exit status of the containing function or sourced script.