How to call bash functions

One way to do this, that involves a bit more typing, is via the source command. To call a function from myFunc you could use source myFunc; ls2 and it would output Hello World.

So for example, I have a file called say.sh:

#!/bin/bash

function talk()
{
        echo "hi!"
}

now I want to call it's talk() function from the command line:

[john@awesome ~]$ source say.sh; talk
hi!

to call it from another bash script:

#!/bin/bash
source say.sh
talk

You can also put each in a separate script and add them in a directory which is in your PATH variable.

so for example, in one script called hello you'd have:

#!/bin/bash
echo "Hello World"

now put it in one of the directories in your PATH, which you can view by running echo $PATH. You can add another directory to your PATH if you'd like or use an existing one. Once you've copied the file there, make it executable with chmod +x filename.

If you are like me, you dont want to clutter your environment with functions. You also have a group of functions that belong together in terms of what they do, so putting them in the same script file makes sense. (I know that a folder with multiple files could serve the same purpose). Here is a possible solution that allows you to call a specific function in the script:

$ cat functions.sh    
#!/bin/bash

ls2() {
        echo "Hello World"
}

ls3() {
        echo "Testing $*"
}

# the next line calls the function passed as the first parameter to the script.
# the remaining script arguments can be passed to this function.

$1 $2 $3 $4 $5 

$ ./functions.sh ls2    
Hello World   
$ ./functions.sh ls3    
Testing     
$ ./functions.sh ls3 first_arg    
Testing first_arg    
$

Another approach would be to create a script called functions.sh ( in the ~/bin directory for example) .

In this script, you add all your personal function definitions (let's say every time you add a function you add it to this file...)

Finally you just have to add the source ~/bin/functions.sh line to your .bashrc file. This way you will be able to call them from the command line, your .bashrc will stay clean, and you will have a specific place for your personal functions.

The dot operator or source builtin in bash is analogous to the import statement in Java.

You can read more about the dot operator or the source builtin.