Basic Terminal Commands Not Working

Question

I'm having trouble using basic commands in terminal that I've been able to use in the past. For example, if I type "dir," I get "-bash: dir: No such file or directory"
I'm know sure what "bash" is, or if that has anything to do with it.
I'm also trying to use the tar command, which I've not used before. Again, I get a similar error: "-bash: tar: No such file or directory"
Hope you can help. Thanks!

Answer 1

Here is an overview of the terminal commands.  Lets assume that your account has a short user name of mac.
Macintosh-HD -> Applications -> Utilities -> Terminal
#What is my short user name?  Type the whoami command.
mac $ whoami
mac
mac $
#How to list all of your disks.
# The ls command is for list
mac $ ls /Volumes/
Audio CD       Macintosh-HD   Spotless       Tiger-ext
mac $
  # Let's say your flash drive is named Spotless
# cd is change directory
mac $ cd /Volumes/Spotless
# pwd is print working directory
mac $ pwd
/Volumes/Spotless
mac $
  # The ls command is for list # l is long # F is type of file where / is directory mac $ ls -lF
total 134704
-rw-r--r--     1 mac  staff     64560 Mar  3  2009 A-picture-of-Youpi-key.png
drwxr-xr-x    83 mac  staff      2822 Nov  7 14:52 Applescript files/
drwxrwxrwx    12 mac  staff       408 Dec 13  2008 Christmas Cards/
drwxr-xr-x     9 mac  staff       306 Dec 21 17:39 Christmas Cards 2009/
... trimmed ... What does all this mean?
drwxrwxrwx
d = directory
r = read
w = write
x = executeable program
drwxrwxrwx
||  |  |
||  |   all other users not in first two types
||  | 
||  group
||
|owner
| 
What type of entery is this? d = directory, - = file, etc. 
Every Unix resource: files, folders, etc has an owner, group, other 
A Unix resource has one owner.
A Unix resource has one group.  A group contains a list of users.
To gain access to a file.  You can be the owner, in the group, or not being the owner or in the group you ended up as other. The owner, group, or other  has read, write, or execute permissions.
# l is long
# a is all to show hidden files & folders
mac $ ls -lFa
total 134736
drwxr-xr-x    41 mac   staff      1496 Dec 22 17:11 .
drwxrwxrwt     8 root  admin       272 Dec 24 13:55 ..
-rwxrwxrwx     1 mac   staff     15364 Dec 23 12:52 .DS_Store*
drwx------     4 mac   staff       136 Jan 22  2009 .Spotlight-V100
drwxrwxrwt     5 mac   staff       170 Sep 14 16:36 .TemporaryItems
d-wx-wx-wx     4 mac   staff       136 Dec 31  1969 .Trashes
-rw-r--r--     1 mac  staff     64560 Mar  3  2009 A-picture-of-Youpi-key.png
drwxr-xr-x    83 mac   staff      2822 Nov  7 14:52 Applescript files
drwxrwxrwx    12 mac   staff       408 Dec 13  2008 Christmas Cards
drwxr-xr-x     9 mac   staff       306 Dec 21 17:39 Christmas Cards 2009
... trimmed ...
# mv is move or rename
mv -i the-name the-new-name
# You can just rename the file back to what it was with mv command.
mv -i old-name new-name
Here is what these commands mean:
cd is change directory
pwd is a print working directory
ls is list
sudo is Super user do
mv is move or rename
For cryptic comments, you can always uses the manual command which is man. For example:
man mv 
# Type the letter q to quit.
In case you have spaces in your filenames or directories, you need to escape them. See examples: 
mac $ ls -l ~/"see it"
-rw-r--r-- 1 mac staff 3171 Oct 26 23:38 /Users/mac/see it
mac $
mac $ cd /Users/mac/Desktop/ttt\ html\ copy/
Do you know about tabing? Type in a few letters of a name then press the tab key. The computer will type out the rest of the name if it is unique.
Press the up arrow key to see the previous command(s).
To edit a command, use the left arror key to more left and the right arror key to move right.  Use the delete key to delete the key to the left.  Type a letter to insert.
history to see many previous commands. 
mac $ history
    2  man launchd.conf
    3  history
http://discussions.apple.com/thread.jspa?threadID=2692161&tstart=0 
Robert