The difference between a Linux shell source and a.

First, use '. ' Perform1. Contents of the file:

a.sh

#!/bin/sha=2echo a= $a

b.sh

#!/bin/sh./a.shecho a.sh:a= $a

2. Add executable permissions

# chmod +x a.sh b.sh

3. Running

#./b.sh a=2a.sh:a=

It can be seen that a in b.sh does not get the A variable in a.sh, it just executes the a.sh once.

second, using Source to execute

1. Contents of the file:

a.sh

#!/bin/sha=2echo a= $a

b.sh

#!/bin/shsource./a.shecho a.sh:a= $a

2. Add executable permissions

# chmod +x a.sh b.sh

3. Running

#./b.sh a=2a.sh:a=2

A variable in a.sh is obtained in the visible b.sh

Iii. Conclusion

In fact, '. ' Just executes the shell script once, and source is adding code from the shell script to the current script, similar to the Include in C.

We'll use Bash-x to see the details.

1) '. ' The way

# sh-x b.sh +./a.sha=2+ echo a.sh:a=a.sh:a=

2) Source of the way

# sh-x b.sh + source./a.sh++ a=2++ echo a=2a=2+ Echo a.sh:a=2a.sh:a=2

Can see '. ' The way only executes the a.sh and outputs the results of a.sh a=2; The source method is to add the a.sh code to the b.sh and then execute.

The difference between a Linux shell source and a.