How directly use scripts in Linux terminal

In Linux, when we write a script, we must use an explicit path to use the script, for example: ./helloworld. If enter helloworld directly, we will be prompted Command 'helloworld' not found, which is very inconvenient.

The reason is the system automatically searches all bin directories contained in the $PATH environment variable to find the commands used. We look at the $PATH and see:

$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

These directories are separated by colons. For example, use nano will searched and found /bin/nano.

So we need to create a bin directory under our user directory ~ and move the script into this directory (if there is a /home/username/bin or ` ~/bin directory in your variable $PATH`, you can use it directly without the below operation):

$ mkdir bin
$ mv helloworld bin

Add below to ~/.bashrc file (if there is not ~/.bashrc, create one):

export PATH=~/bin:"$PATH"

But now you will notice that using command directly still doesn’t work, beacuse bin created is not in $PATH. We can quit terminal and reopen or reboot, system will automatically add it to $PATH. If not convenient to reboot, you can use below command to active:

$ source .bashrc

or

$ . .bashrc

. is the same as the source command. It is a built-in command of the shell to read a specified shell command and treat it as keyboard input.

I hope these will help someone in need~