What does ./ mean, specifically when it's ./configure in full form? (I just installed the macromedia flash player, and they had ./install-flash..., so now I'm curious).

Thanks for any info.

The shell will not execute files in the current directory without the ./ prefix, otherwise it searches through the directories listed in the PATH environment variable.

. = current directory

.. = previous directory.

So say you had a file in /bin called "program".

you could do:

/bin/program -- to execute it.

But say you were already in the /bin directory. You can do

./program

Let me give this one a try.

First some background:

1. The single dot is a shorthand for the name of the current directory that you're in. Think of it as a stand-in for the name of the directory you're in without the trailing slash. (Type "pwd" at the command prompt to print your current "working" directory).

2. The system maintains a list of directories where it will search for executable files such as programs, like "gimp" for example, or for scripts like "configure". To see where the system will look, type "echo $PATH" at the command prompt.

3. If more than one copy of a program or script exists within these directories, then the first one encountered in the list will be the one that is executed. For example, "configure" scripts are found in many locations. The one that gets run may not be the one that you had intended.

4. Unlike DOS, Linux does not automatically look into your current directory for an executable unless a dot "." happens to be in your PATH. For security reasons some people think it's a bad idea to add the current directory to a PATH statement. (This is beyond me. I read it in a book).

So to answer your question, placing "./" in front of a program or script name is simply a safeguard to ensure that the program that you end up running is the one that you're probably looking at right now in your current directory and not some similarly named program residing in a directory somewhere upstream in your PATH.

Thanks, storm3x, that's a very good explanation.

@ contrasutra - is it safe to assume if '..' is previous directory, then '...' is the directory before that and '....' (etc.)?

No, it is not. "." and ".." work just like in DOS and more dots won't work. If you want to go right at the top of the directory tree type "cd /".

Thanks a bunch, guys, that helps.