UNIX File Manipulation

Some Definitions

file

-- the basic unit of storage in UNIX. can be text, a program, a gif (picture), a sound file, etc.

directory

-- a special file where the UNIX system stores information about other files. it's a place to store things, a folder. files and other directories can be contained in directories, you can work in directories.

home directory

-- this is the directory you are in when you first log in. My home directory is at
/afs/rpi.edu/home/35/escobj. It's also referenced as ~escobj.

current working directory

-- the directory you are currently working in, duh! When you first log in, your current working directory (or just ``working directory'') is your home directory. You can change to another directory, in which case, the directory you just moved to becomes your current working directory.

absolute pathname

-- The UNIX file system organizes its files and directories in an inverted tree structure with the root directory at the top. An absolute pathname tells you the path of directories you must travel to get from the root directory to the directory or file you want. In a pathname, delimit directory names with a slash(/). For example, /afs/rpi.edu/home/86/steubg/public/idkfa.wad is an absolute path to the file idkfa.wad which is a cool DOOM wad that my friend Gregg made last year.

relative pathname

-- the pathname of a file or directory relative to your current working directory. Similar to the absolute pathname, you can go through more than one directory level by naming the directories along the path. Use ``..'' to go up the directory tree and use the name of the directory to go down the directory tree.

Some Commands

cd

-- change directory

pwd

-- print working directory

ls

-- list

cat

-- concatenate

more

-- just plain ``more''

OK, Now What?

• Once you have somewhat of a grasp on cd, pwd, and ls, try the following exercise:

  
  Go to your home directory.               Enter cd
  Find your working directory.             Enter pwd
  Change to new working directory.         Enter cd /usr
  List files in new working directory      Enter ls
  Change directory to root and list files. Enter cd /; ls
  Change to a new directory.               Enter cd etc
  Give a wrong pathname.                   Enter cd xqk
  Change to a new directory with           Enter cd /usr
  absolute pathname.
  List files in another directory.         Enter ls /usr/local/bin
  Find your working directory              Enter pwd
  (Notice that ls didn't change it).
  Return to home directory.                Enter cd
  

• And once you get the idea of cat and more, try poking around in different directories and looking at files. If you know a friend's home directory, cd into it and see what's in his/her public directory. Try to look at the contents of some of the files you find there (using cat and more of course).