chmod and permissions

Anon

I have a PHp uploader that seems to not want to let me upload files.....

I think that the permissions may not be set correctly. Does anyone know any sites explaining permissions and use of chmod or can explain to me how to make a file running on user 'nz' upload files to a directory of another user 'au'

any help and command lines would be greatly appreciated, im sitting here with unix websites open everywhere and having the devil of a time trying to figure it out.

mike

Anon

i hope this might help you. You you need to change the command for write and read and most file use it. on the command line enter chmod 755 filename

Basic File Commands: These are typed at the shell prompt host:~>.
ls
List the files in the current directory
ls-a
List all the files in the current directory, even the hidden ones
ls -F
As above, but indicate sub-directories by appending a backslash (/) to their name
cp FILE1 FILE2
Make a copy of FILE1 and call the copy FILE2
mv FILE1 FILE2
Rename a file from old name FILE1 to new name FILE2
mv FILE1 DIR/
Move a file from it's present directory into another directory (DIR)
rm FILE
Remove or delete FILE
more FILE
Display the contents of FILE, pausing after each screenful

--More--(18%)
Whenever you see something like the above at the bottom of your screen, you can:

press the space bar
To see the next screenful of text
type b
To go back one screenful
type q
To quit the listing of text and return to the Unix shell prompt

Correcting Typing Mistakes: (at the Shell Prompt)
Delete or Backspace
Erase the last character you typed
Ctrl-u
Delete the last line you typed

Basic Directory Commands: These are typed at the shell prompt host:~>.
In Unix your files are organized in directories and subdirectories. When you first log in to your account, you are
placed in your home directory, which you can refer to with the character ~.

cd DIR
Go to the directory called DIR
cd ..
Go to the directory above the current directory
mkdir DIR
Create a new directory called DIR
rmdir DIR
Remove the directory DIR (must be empty first; if not, use rm -r)
cd or cd ~
Go to your home directory
mv DIR1 DIR2
Move or rename a directory from old name DIR1 to new name DIR2

Use the / character to separate directory and file names when specifying a path.

Printing
You can print Unix files and mail messages to both your own printer and a network printer. The latter is easier
but requires that you walk to the network printer to pick up your output.

Printing On a Sweet Hall Printer
To print a Unix text or PostScript file, type the following command at the system prompt:
lpr -PNAME FILE ->

where NAME is the name of the printer, e.g., sweet0.

Printing to Your Own Printer
To print a Unix file on your own printer, you must first "download" it to your desktop computer. Exactly how
you do this depends on which communication package you use, as well as which type of computer you have.
These instructions apply only to IBM PCs (and compatibles) that are running under DOS, are linked to SUNet
via Ethernet, and have the ftp protocol installed.

At the DOS prompt (assumed here to be C:>), enter:

C:> ftp HOSTNAME
Connects your PC to HOSTNAME
(username) userid
Your account on the host
Password: xxxxxx
Replace xxxxxx with your password
ftp> cd DIRECTORY
Change to DIRECTORY
ftp> get FILENAME
Copies FILENAME to PC
ftp> quit
Exit ftp and go to DOS
C:> copy FILENAME lpt1
Prints FILENAME on lpt1

Useful Commands
exit
Ends your work on the Unix system
Ctrl-l or clear
Clears the screen
Ctrl-c
Stops the program currently running
Ctrl-p
Retrieves the last shell command you typed
Ctrl-z
Pauses the currently running program
man COMMAND
Looks up the Unix command COMMAND in the online manual pages
find . -name FILE -print
Finds all paths containing FILE in the current directory or below it

fgrep -i PATTERN FILE
Searches for and displays all lines in file that contain PATTERN (case
insensitive)
finger USER@ADDRESS
Displays login/e-mail status of a user at another host
jobs
Lists background jobs started during your current login session
ps

http://www.bsd.org/unixcmds.html
Lists all jobs (background and foreground) started during your login session

du
Displays disk usage in kbytes by directory, starting in the current directory
and working down
du -s
Displays total disk usage
fs listquota
Displays your current disk space usage and quota in kbytes
telnet ADDRESS
Logs on to another machine on the Internet on which you have an account
ftp ADDRESS
Begins a file transfer session with another computer on the Internet
wc FILE
Counts the lines, words, and characters in FILE
spell FILE
Reports possible misspelled words in FILE
webster WORD | more
Looks up a word via the online version of Webster's dictionary

Unix Shell Short Cuts

The Unix shell keeps a record of the commands you type during your login session. Here are a few commands
that take advantage of this history facility. All are typed at the shell prompt host:~>.
history
List all commands typed so far (default maximum number=20)
!!
Repeat the last command
!n
Repeat command n from the history list
!PATTERN
Repeat last command beginning with PATTERN
^{PATTERN1^PATTERN2}
Repeat last command but replace PATTERN1 (usually a typo) with
PATTERN2 (the correction)

Unix Command Summary

See the Unix tutorial for a leisurely, self-paced introduction on how to use the commands listed below. For
more documentation on a command, consult a good book, or use the man pages. For example, for more
information on grep, use the command man grep.

Contents

 cat --- for creating and displaying short files 
 chmod --- change permissions 
 cd --- change directory 
 cp --- for copying files 
 date --- display date 
 echo --- echo argument 
 ftp --- connect to a remote machine to download or upload files 
 grep --- search file 
 head --- display first part of file 
 ls --- see what files you have 
 lpr --- standard print command (see also print ) 
 more --- use to read files 
 mkdir --- create directory 
 mv --- for moving and renaming files 
 ncftp --- especially good for downloading files via anonymous ftp. 
 print --- custom print command (see also lpr ) 
 pwd --- find out what directory you are in 
 rm --- remove a file 
 rmdir --- remove directory 
 rsh --- remote shell 
 setenv --- set an environment variable 
 sort --- sort file 
 tail --- display last part of file 
 tar --- create an archive, add or extract files 
 telnet --- log in to another machine 
 wc --- count characters, words, lines

cat

This is one of the most flexible Unix commands. We can use to create, view and concatenate files. For our first
example we create a three-item English-Spanish dictionary in a file called "dict."

% cat >dict
red rojo
green verde
blue azul
<control-D>
%

<control-D> stands for "hold the control key down, then tap 'd'". The symbol > tells the computer that what is
typed is to be put into the file dict. To view a file we use cat in a different way:

% cat dict
red rojo
green verde
blue azul
%

If we wish to add text to an existing file we do this:

% cat >>dict
white blanco
black negro
<control-D>
%

Now suppose that we have another file tmp that looks like this:

% cat tmp
cat gato
dog perro
%

Then we can join dict and tmp like this:

% cat dict tmp >dict2

We could check the number of lines in the new file like this:

% wc -l dict2
8

The command wc counts things --- the number of characters, words, and line in a file.

chmod

This command is used to change the permissions of a file or directory. For example to make a file essay.001
readable by everyone, we do this:

% chmod a+r essay.001

To make a file, e.g., a shell script mycommand executable, we do this

% chmod +x mycommand

Now we can run mycommand as a command.

To check the permissions of a file, use ls -l . For more information on chmod, use man chmod.

Use cd to change directory. Use pwd to see what directory you are in.

% cd english
% pwd
% /u/ma/jeremy/english
% ls
novel poems
% cd novel
% pwd
% /u/ma/jeremy/english/novel
% ls
ch1 ch2 ch3 journal scrapbook
% cd ..
% pwd
% /u/ma/jeremy/english
% cd poems
% cd
% /u/ma/jeremy

Jeremy began in his home directory, then went to his english subdirectory. He listed this directory using ls ,
found that it contained two entries, both of which happen to be diretories. He cd'd to the diretory novel, and
found that he had gotten only as far as chapter 3 in his writing. Then he used cd .. to jump back one level. If
had wanted to jump back one level, then go to poems he could have said cd ../poems. Finally he used cd with
no argument to jump back to his home directory.

Use cp to copy files or directories.

% cp foo foo.2

This makes a copy of the file foo.

% cp ~/poems/jabber .

This copies the file jabber in the directory poems to the current directory. The symbol "." stands for the current
directory. The symbol "~" stands for the home directory.

date

Use this command to check the date and time.

% date
Fri Jan 6 08:52:42 MST 1995

echo

The echo command echoes its arguments. Here are some examples:

% echo this
this
% echo $EDITOR
/usr/local/bin/emacs
% echo $PRINTER
b129lab1

Things like PRINTER are so-called environment variables. This one stores the name of the default printer ---
the one that print jobs will go to unless you take some action to change things. The dollar sign before an
environment variable is needed to get the value in the variable. Try the following to verify this:

% echo PRINTER
PRINTER

ftp

Use ftp to connect to a remote machine, then upload or download files. See also: ncftp

Example 1: We'll connect to the machine fubar.net, then change director to mystuff, then download the
file homework11:

% ftp solitude
Connected to fubar.net.
220 fubar.net FTP server (Version wu-2.4(11) Mon Apr 18 17:26:33 MDT 1994) ready.
Name (solitude:carlson): jeremy
331 Password required for jeremy.
Password:
230 User jeremy logged in.
ftp> cd mystuff
250 CWD command successful.
ftp> get homework11
ftp> quit

Example 2: We'll connect to the machine fubar.net, then change director to mystuff, then upload the file
collected-letters:

The ftp program sends files in ascii (text) format unless you specify binary mode:

ftp> binary
ftp> put foo
ftp> ascii
ftp> get bar

The file foo was transferred in binary mode, the file bar was transferred in ascii mode.

grep

Use this command to search for information in a file or files. For example, suppose that we have a file dict
whose contents are

red rojo
green verde
blue azul
white blanco
black negro

Then we can look up items in our file like this;

% grep red dict
red rojo
% grep blanco dict
white blanco
% grep brown dict
%

Notice that no output was returned by grep brown. This is because "brown" is not in our dictionary file.

Grep can also be combined with other commands. For example, if one had a file of phone numbers named
"ph", one entry per line, then the following command would give an alphabetical list of all persons whose name
contains the string "Fred".

% grep Fred ph | sort
Alpha, Fred: 333-6565
Beta, Freddie: 656-0099
Frederickson, Molly: 444-0981
Gamma, Fred-George: 111-7676
Zeta, Frederick: 431-0987

The symbol "|" is called "pipe." It pipes the output of the grep command into the input of the sort command.

For more information on grep, consult

% man grep

head

Use this command to look at the head of a file. For example,

% head essay.001

displays the first 10 lines of the file essay.001 To see a specific number of lines, do this:

% head -20 essay.001

This displays the first 20 lines of the file.

Use ls to see what files you have. Your files are kept in something called a directory.

% ls
foo letter2
foobar letter3
letter1 maple-assignment1
%

Note that you have six files. There are some useful variants of the ls command:

% ls l*
letter1 letter2 letter3
%

Note what happened: all the files whose name begins with "l" are listed. The asterisk (*) is the " wildcard"
character. It matches any string.

lpr

This is the standard Unix command for printing a file. It stands for the ancient "line printer." See

% man lpr

for information on how it works. See print for information on our local intelligent print command.

mkdir

Use this command to create a directory.

% mkdir essays

To get "into" this directory, do

% cd essays

To see what files are in essays, do this:

% ls

There shouldn't be any files there yet, since you just made it. To create files, see cat or emacs.

More is a command used to read text files. For example, we could do this:

% more poems

The effect of this to let you read the file "poems ". It probably will not fit in one screen, so you need to know
how to "turn pages". Here are the basic commands:

 q --- quit more 
 spacebar --- read next page 
 return key --- read next line 
 b --- go back one page

For still more information, use the command man more.

Use this command to change the name of file and directories.

% mv foo foobar

The file that was named foo is now named foobar

ncftp

Use ncftp for anonymous ftp --- that means you don't have to have a password.

% ncftp ftp.fubar.net
Connected to ftp.fubar.net

get jokes.txt

The file jokes.txt is downloaded from the machine ftp.fubar.net.

This is a moderately intelligent print command.

% print foo
% print notes.ps
% print manuscript.dvi

In each case print does the right thing, regardless of whether the file is a text file (like foo ), a postcript file
(like notes.ps, or a dvi file (like manuscript.dvi. In these examples the file is printed on the default printer.
To see what this is, do

% print

and read the message displayed. To print on a specific printer, do this:

% print foo jwb321
% print notes.ps jwb321
% print manuscript.dvi jwb321

To change the default printer, do this:

% setenv PRINTER jwb321

pwd

Use this command to find out what directory you are working in.

% pwd
/u/ma/jeremy
% cd homework
% pwd
/u/ma/jeremy/homework
% ls
assign-1 assign-2 assign-3
% cd
% pwd
/u/ma/jeremy
%

Jeremy began by working in his "home" directory. Then he cd 'd into his homework subdirectory. Cd means "
change directory". He used pwd to check to make sure he was in the right place, then used ls to see if all his
homework files were there. (They were). Then he cd'd back to his home directory.

Use rm to remove files from your directory.

% rm foo
remove foo? y
% rm letter*
remove letter1? y
remove letter2? y
remove letter3? n
%

The first command removed a single file. The second command was intended to remove all files beginning with
the string "letter." However, our user (Jeremy?) decided not to remove letter3.

rmdir

Use this command to remove a directory. For example, to remove a directory called "essays", do this:

% rmdir essays

A directory must be empty before it can be removed. To empty a directory, use rm.

rsh

Use this command if you want to work on a computer different from the one you are currently working on.
One reason to do this is that the remote machine might be faster. For example, the command

% rsh solitude

connects you to the machine solitude. This is one of our public workstations and is fairly fast.