same variable in different scripts in bash

Question

What better way to use same variable in two different bash scripts?

Simple example:

./set.sh 333
./get.sh
> 333
./set.sh 111
./get.sh
> 111

And how initialize that variable first time?

UPD:

$ cat get.sh
echo "$var"
$ cat set.sh
export var="$1"
$ chmod +x set.sh get.sh 
$ source set.sh
$ ./set.sh u
$./get.sh

$ source ./set.sh 2
$ ./get.sh
2

fedorqui · Accepted Answer · 2014-02-13 10:42:15Z

1

You can have your scripts as:

cat set.sh 
export var="$1"

cat get.sh 
echo "$var"

chmod +x set.sh get.sh

Then call them:

. ./set.sh 333
./get.sh 
333

Please note that . ./set.sh OR source ./set.sh is called sourcing in the script which makes sure that set.sh is executed without creating a sub-shell and variables set in that script are accessible in the other scripts.

edited Feb 13, 2014 at 10:42

fedorqui

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answered Feb 13, 2014 at 10:38

anubhava

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4 Comments

Stepan Loginov Over a year ago

I use source set.sh -> ./set.sh 1 -> ./get. No result.

anubhava Over a year ago

Have your scripts exactly as I wrote in my answer. Then do: source ./set.sh 222 followed by ./get.sh

Stepan Loginov Over a year ago

There is no way put source into set.sh script?

anubhava Over a year ago

You can put source command in set.sh but unfortunately source will be done in a sub shell. Just understand that when you run a script as ./.set.sh it is executed in sub-shell and all the changes made in sub-shell are not reflected in parent (current) shell.

Beano · Accepted Answer · 2014-02-13 11:29:38Z

1

What you need to understand is the lifetime of a shell variable (or an environment variable as you are using).

When you run a sub-shell, you are running a child process of the shell, and any shell variables that you set exist for the lifetime of the script. Any environment variables (shell variables are "promoted" to environment variable by the use of export) are copied into the environment of the child process - so changes to environment variables in a child process have NO effect on the value in the parent process.

So what you need to use is source which executes the contents of the script in the current shell (no sub-shell is spawned). Always source set.sh and you should be OK

edited Feb 13, 2014 at 11:29

answered Feb 13, 2014 at 11:21

Beano

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Comments

michas · Accepted Answer · 2014-02-13 10:37:47Z

0

You have to store that number in a file.

A called shell script is not able to change the variables of the calling shell.

Another way is to source the shell script instead of running it as a separate process.

But maybe you should explain why you think, that you need that feature. Maybe some totally different solution is even better.

answered Feb 13, 2014 at 10:37

michas

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1 Comment

Stepan Loginov Over a year ago

I have script A, and autocomplete script for this script B. Scripts B and A use same conf file. I need way to change path to conf file in both script (path in variable). source B is already done. So i need way change variable of B script in A script.

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