Use eval.

If you have your source (in /tmp/other.sh):

a=1
b=2
c=3

And you want only a portion, you can use eval to get just those items (here in /tmp/main.sh):

eval $(source /tmp/other.sh;
       echo a="$a";
       echo b="$b";)

echo a is $a "(expect 1)"
echo b is $b "(expect 2)"
echo c is $c "(expect nothing)"

And running it:

$ bash /tmp/main.sh
a is 1 (expect 1)
b is 2 (expect 2)
c is (expect nothing)

WARNING: Performing an eval on an untrusted source is very dangerous. You're executing a shell script, and that script can perform anything you could do yourself. WARNING

Use eval.

If you have your source (in /tmp/other.sh):

a=1
b=2
c=3

And you want only a portion, you can use eval to get just those items (here in /tmp/main.sh):

eval $(source /tmp/other.sh;
       echo a="$a";
       echo b="$b";)

echo a is $a "(expect 1)"
echo b is $b "(expect 2)"
echo c is $c "(expect nothing)"

And running it:

$ bash /tmp/main.sh
a is 1 (expect 1)
b is 2 (expect 2)
c is (expect nothing)

WARNING: Performing an eval or source on an untrusted script is very dangerous. You're executing a shell script, and that script can perform anything you could do yourself. WARNING

Use eval.

If you have your source (in /tmp/other.sh):

a=1
b=2
c=3

And you want only a portion, you can use eval to get just those items (here in /tmp/main.sh):

eval $(source /tmp/other.sh;
       echo a="$a";
       echo b="$b";)

echo a is $a "(expect 1)"
echo b is $b "(expect 2)"
echo c is $c "(expect nothing)"

And running it:

$ bash /tmp/main.sh
a is 1 (expect 1)
b is 2 (expect 2)
c is (expect nothing)

Use eval.

If you have your source (in /tmp/other.sh):

a=1
b=2
c=3

And you want only a portion, you can use eval to get just those items (here in /tmp/main.sh):

eval $(source /tmp/other.sh;
       echo a="$a";
       echo b="$b";)

echo a is $a "(expect 1)"
echo b is $b "(expect 2)"
echo c is $c "(expect nothing)"

And running it:

$ bash /tmp/main.sh
a is 1 (expect 1)
b is 2 (expect 2)
c is (expect nothing)

WARNING: Performing an eval on an untrusted source is very dangerous. You're executing a shell script, and that script can perform anything you could do yourself. WARNING