Files are stored on a hard disk that is mounted on the UNIX system. If you and a coworker are both using the same system, then the file /departments/writers/meetings/minutes.txt that you see on your terminal can also be accessed on your coworker’s terminal under the same pathname.
This means that on a UNIX system, you don’t have to deal with trading floppy disks to give a file to someone else. You can just tell someone the pathname to the file, and they should be able to find it on the system.
Or at least, that’s the theory. In actuality, there are security measures for preventing people from seeing or editing files that you don’t want them to. There are also complications with more than one person being able to work on the same files: how do you make sure that you aren’t both making changes at the same time?
Why can’t I read a file or list a directory?
How do I let my coworkers edit my files?
I made changes to a file, but now I find out that I can’t write it. Are my changes lost?
How can I be sure that no one else is working on this file right now?
This chapter explains the concepts behind sharing files on UNIX and describes how you might deal with these questions in the absence of your system administrator.