How to return data from a bash shell script subroutine?

Question

Given the following two executable scripts:

----- file1.sh

#!/bin/sh
. file2.sh
some_routine data

----- file2.sh

#!/bin/sh
some_routine()
{
    #get the data passed in
    localVar=$1
}

I can pass 'data' to a subroutine in another script, but I would also like to return data.

Is it possible to return information from some_routine?

e.g: var = some_routine data

Just fyi, you can't have a space in the assignment: `var=$(some_routine data) — Kevin
– Kevin, Commented Mar 14, 2012 at 23:12

Amber · Accepted Answer · 2012-03-14 23:00:59Z

8

Have the subroutine output something, and then use $() to capture the output:

some_routine() {
    echo "foo $1"
}

some_var=$(some_routine bar)

answered Mar 14, 2012 at 23:00

Amber

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2 Comments

jofel Over a year ago

This and other solutions are discussed at linuxjournal.com/content/return-values-bash-functions

TERACytE Over a year ago

Thank-you for the responses. The option provided by Amber works, but not in my case. My routines echo various status messages and can return an early response. I tried the second option under the link that jofel provided and it works perfectly for me. jofel, can you please respond to my question with that answer? I will mark it as the solution.

kappa · Accepted Answer · 2012-03-14 23:02:27Z

0

It's not allowed, just set the value of a global variable (..all variables are global in bash)

answered Mar 14, 2012 at 23:02

kappa

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Comments

Umae · Accepted Answer · 2012-03-15 08:45:37Z

0

if

some_routine() {
    echo "first"
    echo "foo $1"
}

some_var=$(some_routine "second")
echo "result: $some_var"

they are ok.But the result seems to be decided by the first "echo".Another way is use "eval". some_var return "first"

some_routine()
{
        echo "cmj"
        eval $2=$1
}

some_routine "second" some_var
echo "result: $some_var"

in this way, some_var return "second".The bash don't return a string directly.So we need some tricks.

answered Mar 15, 2012 at 8:45

Umae

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