Running a program from terminal, "command not found"

I'm new to Ubuntu, and trying to start opening and running programs directly from the terminal. I've tried this multiple times with different programs, and always get the same error -- "command not found". I've tried running programs both from the main directory and from the sub-folder the program is in, but neither work.

Any tips?

Here's what I've been getting:

When I try running in the folder:

Julia@a-capella: ~Documents/events_adc$ nuetrino_s1_1
nuetrino_s1_1: command not found

When I try running from the main directory:

ulia@a-capella: ~$ nuetrino_s1_1
nuetrino_s1_1: command not found

Oddly enough, firefox (and no other programs I've tried) will run from here.

Thanks!

Solution 1:

If you type the command

echo $PATH

it will display your command path, or where commands are searched for. Your current directory would be shown as a "." if its there (i very much doubt it) which is what you're probably missing.

The easiest way to run commands in your current directory is:

./nuetrino_s1_1

The ./ part tells the system to look for the command in the current directory [or $PWD, or present.working.directory].