When you write your own scripts, you want to put them in a directory that's added to your $PATH environment variable. To see which directories are included in your $PATH, type
at the CLI (Command Line Interface); the directories in the list are separated by colons ':'.
Note, to copy a script over to any of the directories listed in your $PATH, you more than likely need to be root;
Password: [type in your root password]
# cp -v myscript /copy/to/dir/
If you want to limit who can run the scripts to just you, create a directory in your home dir, and let's call it "bin":
Now, you have to add this directory to $PATH so that bash (assuming you're using bash) will know to look there:
PS. In case you're wondering, the '>>' means append whatever is on the left of it, to the file to the right of the sign.
$ echo "export PATH=$PATH:/home/user/bin" >> ~/.bashrc"