[Pan-users] Re: Help

[Duncan]

"Bill Wright" <address@hidden> posted
address@hidden, excerpted below, on  Mon, 05 Nov
2007 08:22:37 -0500:

> Having been a windows user for many years, I find it difficult
> navigating the linux file system. How do I get to and how do I find
> .pan2 file so that I can rename it?

First thing, keep in mind that an initial dot at the beginning of a 
filename is the Unix/Linux way of marking a file "hidden", something the 
FAT and NTFS filesystems MS uses had/have a file attribute to handle.

So you normally won't see any file starting with a dot.  You can either 
type it in at the command line if that's your thing, or (as on MSWormOS) 
turn on viewing of hidden files in your filemanager, if you prefer that, 
so you can see it and work with it that way.

Second thing, ~/ is a shortcut way of referencing a users home directory, 
normally /home/<username> .  Thus, ~/.pan2 indicates the (hidden) .pan2 
file (or in this case directory) in your home directory.

So for example, if your user's name is "walt", then the directory would 
normally be /home/walt/.pan2 .  If you chose to do the move from the 
command line, you could use commands such as this:

cd
mv .pan2 .pan2.backup

FWIW, cd=change directory.  Without a directory to change to, it defaults 
to changing to the user's home directory, /home/walt/ in our example.  
mv=move.  Note that since the commands above don't mention the home 
directory by name, they should work no matter /what/ your username is, as 
long as your commandline session is as the same user as you use when 
running pan.

Three, off topic for pan, but worthwhile to mention while we are on the 
topic of hidden files that start with a dot,  as this is **VERY** 
**IMPORTANT**:  rm is the remove command.  It has a commandline switch -r 
which means recursive (remove all subdirectories as well) and of course, 
* is a wildcard.  NEVER EVER EVER (EVER EVER EVER!!!) type in a command 
such as rm -r .* 

If you take a look at the hidden .* files in several directories and 
figure out what they reference, you'll see why the above is such a big no-
no.  Similar to the MS filesystems you may be used to, directories 
normally have two "default" entries in them, . (single dot, referring to 
"me", the dir I'm in right now) and .. (double dot, referring to the 
parent dir).  rm -r .* will (or at least used to, I've read that it 
refused now, but obviously I've not tested it) remove .., that is the 
PARENT dir, recursively, including its parent dir, ALL THE WAY TO / , 
that is the root or top dir!  IOW, running that command is a good way to 
be left with an empty disk!

Running the command as a normal user is bad enough -- you usually lose 
all the personal files you might have been saving.  Running it as root... 
well, you can lose your entire system.

A similar effect can be had with a minor typo, a space where it shouldn't 
be, particularly with wildcards, can turn an ordinary rm of a couple of 
stray files into an rm of rather more than intended.  Suppose after 
getting pan working, you want to remove the backup dir created above.
rm -r .pan2.backup, right?  But now, if you are lazy and know the 
only .pan2.* file or dir is .pan2.backup, you might type that instead.  
Great, and it'll do what you wanted, but consider what happens if you get 
a stray space before that *, and type this instead: rm -r .pan2 * !!!

The moral of this point is this:  When deleting (rm-ing) anything, 
particularly hidden files, OR when typing in ANY command as root, get in 
the habit of typing in the command but NOT THE ENTER.  Then sit on your 
hands a moment, and LOOK CAREFULLY at the command.  Make sure it's the 
command you intended, not something else.  When you are SURE it's going 
to have the desired effect, and won't bring a nasty surprise, THEN go 
ahead and hit that ENTER key.  =8^)

The above rule applies double anytime you have a * in the command.

BTW, rm, cp, mv, and similar commands, all have a -i (interactive) switch 
as well.  This will prompt every time the command will overwrite or 
delete an existing file.  Some distributions alias particularly rm to rm -
i for safety, so you get interactive mode by default.  However, don't 
depend on this behavior if you or your distribution DOES choose to use 
the -i alias form, because sure as you do, at some critical point, the 
alias won't be in place when you type the command, and you will WISH you 
hadn't done what you just did.  But knowing about -i and getting in the 
habit of typing it in yourself where appropriate is a good thing.  Used 
well, it can help prevent that sinking feeling you get when you realize 
that rm you typed is taking WAY too long, with the disk still churning 
away long after the single file you THOUGHT you were removing should have 
been gone.

Hopefully that's useful. =8^)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman