Meaning of periods and forward slashes in regards to file locations.

My INI file has this section:

[RS274NGC]
PARAMETER_FILE = linuxcnc.var
RS274NGC_STARTUP_CODE = o<metric_startup> call
SUBROUTINE_PATH = ./:./qtplasmac:../../nc_files/subroutines
USER_M_PATH = ./:./qtplasmac

I know that a colon is a separator of different paths.
I can also find information on Google about the single period followed by the forward slash (./)

However, the last path of SUBROUTINE_PATH which is 
../../nc_files/subroutines
has me a bit stumped, and I can't find any information on that.
What is the meaning of ../.. before the /nc_files/subroutines
 

../ move back one folders
../../ move back two folders

Paths with these are known as relative paths.

You could change these to absolutes paths.
either way - they need to point to the expected folder.

Hope that helps.

Thanks Cmorley,

easy once I know.

Since I posted I actually managed to find a bit more info on them but your description is much simpler. Most Google results talk about parent directory.
I like the way you tell it, move back one or two folders.

Keith

Beefy, I thought you were old enough to remember! 
This is the same as  the good old DOS days. 
. means this folder eg execute ./myscript.sh
.. means parent folder but you can chain them together eg  cd ..

Linux also adds ~ for your home folder. I had to Google that one at the beginning.
eg. cd ~

rodw wrote:

Beefy, I thought you were old enough to remember! 

DOS   (said coughing and gagging).
I think PTSD made me block it out of my mind. Don't remind me about it or I'll have to reach for the meds.

I'll never forget my first laptop with that nasty 3 letter system on it. Cost me $4K and had a "whopping" 120 Megabyte (not a typo) hard drive LOL.
How things have changed.

Wow, a massive 250 MB, double what mine was. Gee you're lucky.

So what are you putting yourself through that hell for. I'm guessing they have a special end purpose.

pfft, my first HDD was 20 mb with 68 Ms seek time. Then upgraded to a voice coil 40mb one with maybe 9 Ms access. A month later it failed and turned  itself into a $1k paperweight!