Question

I am new to shell scripting. I am working on a project where the requirement is like one script file will set the variables and another script file has to get those variables and manipulate it. I am storing the variables from first script into a file and in second script file I am reading it.

In first script file, first.sh , I am doing like

echo "a=6" > test.dat
echo "b=7" >> test.dat
echo "c=8" >> test.dat

I use > for the first variable where it overwrites and for the next values it appends. So the file will have the latest values always.

Is there any better approach than this ?

In the second script file how can read and fill the appropriate values ?

Answer 1

You can load this variables from the script using source:

source test.dat

or just

. test.dat

Example:

$ echo "a=6" > test.dat ; echo "b=7" >> test.dat ; echo "c=8" >> test.dat
$ cat test.dat 
a=6
b=7
c=8
$ . test.dat
$ echo $a $b $c
6 7 8

If you have a script/program that generates these variables, you can also use eval.

Example:

$ cat generate.sh
echo a=6
echo b=7
echo c=8

$ bash generate.sh 
a=6
b=7
c=8

$ eval $(bash generate.sh)
$ echo $a $b $c
6 7 8