Using global variables in functions with parameters in bash

Question

I'm trying to catch a return value from a function in bash, that modify a global variable. Works perfectly with funtions with no parameters:

#!/bin/bash

tes=2
testfunction(){
        tes=3
        tes_str="string result"
        return 0
}
if output=testfunction; then
        echo "OK"
else
        echo "KO"
fi
echo $tes
echo $tes_str

But no with parameters:

#!/bin/bash

tes=2
testfunction(){
        tes=3
        tes_str="string result"
        return 0
}
if output=$(testfunction "AA" "BB"); then
        echo "OK"
else
        echo "KO"
fi
echo $tes
echo $tes_str

Because for bash, parameters ("AA" or "BB") are a command, and I must put it in backets (but if use backets, can't modify global variables). How can I do it? I'm stucked. Regards

Works perfectly with funtions with no parameters No it doesn't, your code is invalid. output=testfunction only assigns the text testfunction to output. — KamilCuk
– KamilCuk, Commented Nov 3, 2020 at 11:26
@Souf : Your first example does not execute testfunction. Your second example does. You can easily verify this by doing a echo heloo >&2 inside testfunction. — user1934428
– user1934428, Commented Nov 3, 2020 at 12:07
Yes, It was a mistake, it's my fault, I wrote the simple code for this post, trying to explain the issue, catching the return value and calling a function with parameters. — Souf
– Souf, Commented Nov 3, 2020 at 17:18

KamilCuk · Accepted Answer · 2020-11-03 11:28:15Z

1

Why use output? Just remove it and run the function.

if testfunction; then

Notes:

output=testfunction is assigning the text testfunction to the variable output.
output=$(testfunction) will not work, because $(...) runs everything inside a subshell.

answered Nov 3, 2020 at 11:28

KamilCuk

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3 Comments

Souf Over a year ago

Because without output assignment, I can't catch the return value. And first option yes, it was a mistake, it's my fault. With if testfunction; then I can't catch the return value, and I can't pass the parameters.

KamilCuk Over a year ago

I do not follow - no, I disagree with your statements. You can "catch" the return value and yes you can pass arguments. With command substitution you save output of a command, you still may do that with temporary file. repl bash example

Souf Over a year ago

Yes, it works... I don't know why yesterday I can't do it... The only response is that I'm stupid... :(

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