Continue on the next page
7. What is the name of the tree-like structure under which all
data is stored?



8. What is the name of the highest level directory?



9. What symbol represents the highest level directory?



10. What is the general syntax of a UNIX command?



11. What is the most common form for listing options on a
command line?



12. What character would you use to erase a character on the
command line?



13. What character terminates the execution of a command?



14. What is the default BourneShell prompt?



15. How can you control the flow of output to your monitor
screen?

1. What annex command is entered to make a connection to the
Multimax?



2. What is the UNIX command to change the password?




3. How long is your password valid?




4. How long do you have to wait before changing your password
again? Why?



5. What UNIX command is used to logout of the Multimax?




6. What is the command to logout of the annex?



COMPUTER EXERCISES

7. Login to the Multimax

a. What did you notice when you entered the password?



b. Can you see the password as you enter it?



c. What happens if you make a mistake while entering the
password?



8. What do you see once you have logged in? Write it here.





9. Enter the command which displays the man pages for the man
command. (Don't forget to control output to the screen.)

The first section is titled "NAME," what are the titles of
the other sections?





10. What are the options for the man command?




11. Enter the command to find out who (hint) is logged into the
system.



12. What command will give you more information about the
current users? Try it.


13. Logout of the Multimax and the Annex.

2. FILES

In UNIX, all data is organized in files. An ordinary file is a
memo, source code program or shell script. A shell script or
program source code can be viewed or edited from your terminal.
Other files contain binary data, like programs for the kernel;
these files cannot be viewed or edited on the terminal.

Peripheral devices such as disks, tape drives, printers, and
terminals are also assigned file names. Device files are
considered to be special files. They have 'special'
characteristics. Although input and output can be redirected to
and from a special file, do not attempt to display the contents
of a special file on your terminal.
3.1 File Access Modes

File access modes are the protections that can be assigned to
files. This protection can protect your files from unauthorized
reading or writing. You can even protect your files from
yourself (you can prevent accidental deletion).

There are three access modes for files:

r (read) read, examine, copy data in a file

w (write) modify, delete a file

x (execute) use the file as a command

Users with access to a file fall into one of three groups:

u (user) the file's owner

g (group) users in the same group

o (other) everybody else

The first output field of the ls -l command is a ten character
field. Characters two through ten describe the file access
modes. A typical access mode listing looks like:

rwxr-xr-x

Of the nine columns, the first three describe modes for the
file's owner, the next three for his group, and the last three
for everyone else. Within each group of three, the first column
describes read access mode, the second write, and the third
execute. A letter in a column indicates access granted, a dash
(-) indicates access denied.

Using the previous example, the user has r (read), w (write), and
x (execute) permissions. Members of the user's logical group can
read ? or execute (x). Everyone else has read ? and execute
(x) permissions, too. The effect of these permissions is that
the file's owner is the only one who can modify the file; but
everyone can examine, copy, or execute the file.
To change access modes on a file or directory, use the chmod
command.

??
? Command Format: chmod <access> <file1[filen]> ?
? ?
? access - access permissions ?
? file1[filen] - one or more files to change permissions ?
??

Access can be expressed in either of two forms:

- with letters: [ugo] [+-=] [rwx]

- with numbers: [0-7] [0-7] [0-7]

Let's look at the method of changing the file permissions with
letters. The letters u, g, and o represent user, group, and
others, respectively. The + (plus) sign means to add the
permission and the - (minus) sign means to remove the permission.
The = (equal) sign means to set the permissions as shown. Of
course, r,w, and x are read, write, and execute.

If, for illustration purposes, we created a file named file1 that
had the following permissions:

rw-rwxrwx

and you want to give yourself (user) execute permission and take
away others' (others' here means group and everyone else) write
permissions.

Sample Session:

??
? $chmod u+x,g-w,o-w file1 ?
? $ ?
??

Now if we use the ls -la command, and look at the file
permissions for file1, they will look like this:

rwxr-xr-x
If you want to set several protections at once use the equal
sign. The following example will set the permissions for the
user to read and execute.

Sample session:

??
? $chmod u=rx file1 ?
? $ ?
??

The second method of changing the permissions is to use the octal
digits (0-7). The octal digits 0 through 7 are represented in
binary in the following manner.

Octal Binary Corresponds to permissions

0 000 ---
1 001 --x
2 010 -w-
3 011 -wx
4 100 r--
5 101 r-x
6 110 rw-
7 111 rwx

Notice that every time a one digit (1) occurs in the binary
number the corresponding permissions are also set. Every time a
zero (0) occurs, the corresponding permission is denied. So to
change the file permissions in the previous example, this is the
command to enter:

Sample Session:

??
? $chmod 755 file1 ?
? $ ?
??

The first octal digit assigns user permissions of read, write and
execute. The second digit assigns the group permission to read
and execute. The last digit sets the others permission to read
and execute too.
3.2 Listing Contents of Directories

The ls command is used to display file names and their
characteristics. Since file names are stored in directories, ls
actually reads directory files. Executing ls with no flags or
arguments simply lists the names of the files that exist in your
current working directory. The initialization files will not be
listed.

?
? Command Format: ls [options] [dir1[dirn]] ?
? ?
? options - see man pages for a complete list ?
? ?
? dir1[dirn] - one or more directory names ?
?

The -a flag will cause the hidden (initialization) and all other
filenames to be displayed.

The -C flag causes the output to be changed from single-column to
multi-column display.

The -F flag adds a character to the end of each displayed
filename:

/ indicates a directory
* indicates the file is executable.
blank indicates a plain or ordinary file

The -l flag causes detailed information to be printed for files
in the directory. This information includes:

file type (directory, block special, character special,
fifo special, symbolic link, or ordinary file)
access modes
number of links
ownership
group affiliation
size in bytes
date and time of last modification
filename
Without a filename argument, ls displays information about the
current working directory. The output is automatically sorted
alphabetically by default.

Example:

.................................................................
. $ls .
.................................................................

The following example provides a long listing of the current
working directory.

Example:

.................................................................
. $ls -l .
.................................................................

This example shows the ls command with no arguments so it uses
the default, the current working directory. The argument could
be a relative or absolute directory name.

Sample session:

??
? $ls -la ?
? total 975 ?
? drwxrwxr-x 4 teacher class 2048 Jul 16 17.56 . ?
? drwxr-xr-x 60 root 1536 Jul 13 14:18 .. ?
? -rwx------ 1 teacher class 4210 May 1 08:27 .profile ?
? -rwxr-xr-x 1 teacher class 1948 May 12 13:42 memo ?
? $ ?
??

3.3 File Classifications

The file command will classify files according to their contents.

??
? Command Format: file [options] <file1[filen]> ?
? ?
? file1[filen] - one or more filenames to analyze ?
??

A few of the classifications that the file command displays are
shown below. The results of using the file command are not
always correct.

English text
ascii text
c program text
cannot stat
commands text
data
directory
empty
executable

Sample Session:

??
? $file speople ?
? speople: commands text ?
? $file test ?
? test: directory ?
? $file mail ?
? mail: data ?
? $ ?
??

By convention, files beginning with a dot (.) are called
initialization files or 'hidden files'. These files describe
your environment to the shell. They are sometimes called 'dot
files'.

By convention, files that end with:

.c are C source code programs
.f are Fortran source code programs
.o are object programs
.a are archive files
3.4 Displaying Files

The cat command displays the contents of a file. The command cat
is an abbreviation for catenate. This command will read each file
in sequence and write it to the monitor screen.

??
? Command Format: cat [options] [file1[filen]] ?
? ?
? options - see man pages for a complete list ?
? ?
? file1[filen] - one or more file names ?
??

If no filename is given, or the argument - is encountered, cat
reads from standard input.

Sample session:

.................................................................
. $cat .
.................................................................

This is the simpliest example but not very exciting. The cat
command will get its input from the keyboard. Everything that is
typed will be displayed on the monitor.

If an argument is given to the cat command that file will be
displayed on the monitor.

Sample session:

??
? $cat main.c ?
? main () ?
? { ?
? printf ("hello from main!\n\n"); ?
? printf ("calling function1!\n\n"); ?
? funct1(); ?
? printf ("back from function1!\n\n"); ?
? printf ("calling function2!\n\n"); ?
? funct2(); ?
? printf ("that's it!\n\n"); ?
? } ?
? $ ?
??
Several files can be displayed on the monitor one after the other
by separating the filenames with a space.

Sample session:

??
? $cat main.c main.f ?
? main () ?
? { ?
? printf ("hello from main!\n\n"); ?
? printf ("calling function1!\n\n"); ?
? funct1(); ?
? printf ("back from function1!\n\n"); ?
? printf ("calling function2!\n\n"); ?
? funct2(); ?
? printf ("that's it!\n\n"); ?
? } ?
? program calling ?
? write(6,100) ?
? 100 format('Hello from main!',/) ?
? write(6,110) ?
? 110 format(' Calling subroutine1!',/) ?
? call sub1 ?
? write(6,120) ?
? 120 format(t15' Back from subroutine1!',/) ?
? write(6,130) ?
? 130 format(' Calling subroutine2!',/) ?
? call sub2 ?
? write(6,140) ?
? 140 format(t15' Back from subroutine2!',/) ?
? write(6,150) ?
? 150 format(' Thats all, folks!') ?
? end ?
? $ ?
??

If the file contains more lines than can be displayed on the
screen the display will continue to scroll until the last line
has been displayed then the prompt will be redisplayed. This can
be a problem if you intend to read the text. Be prepared to stop
the screen so it can be read.
The pg command displays the contents of a file one screen at a
time. It allows the user to perform string searches and to
scroll backwards.

??
? Command Format: pg [options] [file1[filen]] ?
? ?
? options - see man pages for a complete list ?
? ?
? file1[filen] - one or more files to paginate ?
? ?
??

Sample session:


? ?
? $pg memo ?
? What's Happening ?
? by Pam Hajny ?
? Denver Office ?
? ?
? With IRM Training: ?
? ?
. A Reclamation-wide workshop was held in early October to .
. .
. .

? three groups; CYBER, VAX, and other (PC/LAN, scientific, ?
? : ?
? ?


Twenty three lines of the file will appear and the : (colon)
prompt will appear on the last line. To have the next twenty
three line of the file appear, simply press (Ret). If you don't
want to see anymore of the file, enter a q (for quit) and the
shell prompt will be redisplayed.
The following UNIX command is useful for viewing the end of a
file without having to display the entire file.

??
? Command Format: tail [options] [file1] ?
? ?
? options - see man pages for a complete list ?
? ?
? file1 - the file to display, if none is given use ?
? standard input ?
??

The tail command displays the last 10 lines of file by default.
The tail command accepts a -N flag to display the last N lines.

Sample Session:


? $tail memo ?
? data communication between the ASC IBM and other Reclamation computers. ?
? Asynchronous communication can be accomplished with the same terminals ?
? we use for other computer tasks, over the same lines and through the MICOM ?
? port selectors. Currently, host-to-host communications is accomplished ?
? over a line between the IBM and the CYBERs. The software that supports ?
? this communication is called NJEF. Although the capability has been there ?
? for some time, we have recently been working with ASC personnel to ?
? improve its reliability and accessibility. For CYBER users, there is ?
? an NJEF Users' Guide available which can be requested through the Hotline ?
? (303) 236-4567. ?
? $ ?

3.5 Removing Files

The rm command will remove the entries for one or more files from
a directory. If an entry was the last link to the file, the file
will be destroyed. Removal of a file requires write permission
to the directory itself, but neither read nor write permission to
the file itself. The format for the rm command is:

?
? Command Format: rm [options] <file1[filen]> ?
? ?
? options - see man pages for a complete list ?
? ?
? file1[filen] - one or more files to remove ?
?

Sample session:

??
? $ls ?
? memo ?
? tdata ?
? subdir ?
? $rm memo ?
? $ls ?
? tdata ?
? subdir ?
? $ ?
??

The file memo has been deleted from the current working
directory.
Multiple files can be deleted by separating the filenames with a
space.

Sample session:

??
? $ls ?
? memo ?
? tdata ?
? subdir ?
? $rm memo tdata ?
? $ls ?
? subdir ?
? $ ?
??
3.6 Printing Files

The lp command routes a file to a printer.

??
? Command Format: lp [-d<dest>] [-n<number>] [file1[filen]] ?
? ?
? dest - destination (default set by administrator) ?
? ?
? number - number of copies (default is 1) ?
? ?
? file1[filen] - one or more files to be printed ?
??

If no file name is mentioned the standard input is assumed. The
filename dash (-) stands for standard input and may be supplied
in conjunction with named files. The order in which the
filenames appear is the order in which they will be printed.

The printers in Denver have the following destination names:

Mannesman 910 laser printer - mtlzr

Mannesman 600 line printer - mt_600 (Denver default)

If no specific printer is given the default printer will be
selected. The following example will print one copy (default) of
the file called test_285 to the line printer (default).

Sample session:

??
? $lp test_285 ?
? request id is mt_600-1271 (1 file) ?
? $ ?
??

It is possible to specify the printer as shown in the following
example. In this case, we specified the default printer.

Sample Session:

??
? $lp -dmt_600 test_286 ?
? request id is mt_600-1272 (1 file) ?
? $ ?
??



To print two copies of a file called test_287 on the laser
printer in Building 53 in Denver, enter the following command:

Sample Session:

??
? $lp -dmtlzr -n2 test_287 ?
? request id is mtlzr-1273 (1 file) ?
? $ ?
??
3.7 Print Status

The lpstat command will print information about the current
status of the printer system.

??
? Command Format: lpstat [options] ?
? ?
? options - see man pages for a complete list ?
? ?
??

If no options are given, the lpstat command will print the status
of all requests made to lp by the user.

Sample Session:

??
? $lpstat ?
? mtlzr-1274 teacher 22560 Jul 16 09:05 on mtlzr ?
? $ ?
??

The first field is the remote id of the print job. The username
is next and the size (in bytes) of the print file. The date and
time are next and finally the name of the printer.

One of the options available is -t. This option will print all
of the printer status information.

Sample Session:

??
? $lpstat -t ?
? scheduler is running ?
? system default destination: mt_600 ?
? device for mt_600: /dev/rlp000 ?
? device for mtlzr: /dev/rt0002 ?
? mt_600 accepting requests since Sep 19 16:09 ?
? mtlzr accepting requests since Sep 19 16:43 ?
? printer mt_600 is idle. enabled since Jul 3 16:52 ?
? printer mtlzr is idle. enabled since Jul 3 16:51 ?
? $ ?
??

This is an example of the kinds of information available from the
lpstat command.
3.8 Canceling Print Jobs

The cancel command will cancel printer requests made by the lp
command. The command line arguments can be either request id's
(these are returned by the lp command) or the printer name. If
you specify the request id, the cancel command will stop the job
even if it is currently printing. If you specify the printer
name, the job currently being printed will be canceled. In
either case, the cancellation of a request that is currently
printing will free the printer to print the next request.

??
? Command Format: cancel <[ids] [printer]> ?
? ?
? ids - request ids (returned by lp command) ?
? ?
? printer - printer name ?
??

Sample Session:

??
? $lp -dmt_600 contest ?
? request id is mt_600-1280 (1 file) ?
? $cancel mt_600-1280 ?
? request "mt_600-1280" canceled ?
? $ ?
??
3.9 Copying Files

A user may make a copy of a file if he has read access to that
file. The cp command can be used to copy the contents of one
file to another.

??
? Command Format: cp <file1[filen]> <target> ?
? ?
? file1[filen] - one or more source files ?
? ?
? target - file or dirname ?
? ?
? file1 and target cannot be the same and ?
? if the target is a file its' contents are ?
? destroyed. ?
? ?
? If target is a directory, then the contents ?
? of the source file(s) is copied to that ?
? directory. ?
? ?
??

Sample Session:

??
? $cp contest memo ?
? $ ?
??

This will cause a copy of the file contest to be made into a file
named memo. If memo doesn't exist, it will be created. If it
already exists, it will be written over. The cp command is
nondestructive; that means that the source file will remain
intact.

The cp command can also be used to copy several files into
another directory.

Sample Session:

??
? $cp file1 file2 /user0/teacher ?
? $ ?
??

A copy of file1 and file2 has been sent to the directory (in this
case, the target directory) /user0/teacher. The user of cp will
own the newly copied files.
3.10 Moving Files

A user may move a file only if he has write access to that file.
The mv (move) command can be used to rename one file.

??
? Command Format: mv <file1[filen]> <target> ?
? ?
? file1[filen] - one or more source files ?
? ?
? target - file or dirname ?
? ?
? file1 and target cannot be the same and ?
? if the target is a file its' contents are ?
? destroyed. ?
? ?
? If target is a directory, then the contents ?
? of the source file(s) are moved to that ?
? directory. ?
? ?
??

Sample Session:

??
? $mv contest memo ?
? $ ?
??

This will have the effect of changing the name of the file
contest into memo. The permissions on the file will remain the
same. The move command is destructive. That means the source
file no longer exists.

The mv command can also be use to move files from one directory
to another.

Sample Session:

??
? $mv file1 file2 /user0/teacher ?
? $ ?
??

The files, file1 and file2, have been sent to the directory
/user0/teacher. They have been "moved" and no longer reside in
the current directory. The owner remains the same when a file is
moved.
Workshop 3

This workshop will reinforce your understanding of the topics
presented in this chapter. Login to the Multimax using the
username and password given to you by the instructor. Each
student should complete the entire workshop. You might need to
work in a team on the computer exercises.

DESK EXERCISES

1. List four types of files.




2. What does the file command do?




3. The ls command will display the contents of the current
working directory. What does the -F option do?



4. What command is used to display the contents of an ordinary
file?



5. What command would you use to append one file to the end of
another?



6. What is the lp command?



Continue on the next page
7. How can you find out the status of your print job?



8. What command would you enter to cancel a print job called
mt_600-1131?



9. What command will copy the contents of one file to another?



10. What does mv do?



11. What do the following file protections indicate?

rwx------


rwxr-xr-x


---------

rwxr--r--








Continue on the next page
COMPUTER EXERCISES

12. Log into the Multimax.



13. Execute the file command on the files listed below. Record
the output in the space provided.

a. .profile


b. /bin/vax


c. /dev/console



14. Which of the above files is readable?




15. Enter the command to display the contents of the current
working directory. Hint: ls

a. How many files are listed?


b. Type ls -a


c. How many entries are listed?



Continue on the next page
d. Which entries were not listed in your original output
of ls?





16. How does the output of ls -a and ls -Ac differ?
Try it.




17. How many fields are displayed for each entry when you
execute ls -l? What are the fields?



18. What are the current permissions on .profile?



19. Change permissions on .profile so that no one (including
you) has any access to the file.
(Hint: Use the chmod command)



20. Without changing the permissions, list the contents of the
file named .profile to the screen.
What happened? Why?







Continue on the next page
21. Change the permissions on .profile to

u - read, write, execute
g - read
o - read



22. Type cat .profile. What happened? Do you know why?




23. Enter pg memo. What does this command do?





24. Send one copy of the file called memo to the laser printer.




25. Logout of the Multimax and the Annex.
NOTES
??
4. DIRECTORIES

A directory is a file whose sole job is to store file names and
related information. All files, whether ordinary, special, or
directory, are contained in directories.

The directory in which you find yourself when you first login is
called your home directory. You will be doing much of your work
in your home directory and subdirectories that you'll be creating
to organize your files.


4.1 Absolute/Relative Pathnames

As we saw earlier, directories are arranged in a hierarchy with
root (/) at the top. The position of any file within the
hierarchy is described by its pathname. Elements of a pathname
are separated by a /. A pathname is absolute if it is described
in relation to root, so absolute pathnames always begin with a /.
These are some example of absolute filenames.

/etc/passwd
/users/sjones/chem/notes
/dev/rdsk/Os3

A pathname can also be relative to your current working
directory. Relative pathnames never begin with /. Relative to
user sjones' home directory, some pathnames might look like this:

chem/notes
personal/res

To determine where you are within the filesystem hierarchy at any
time, enter the command to print the current working directory.

??
? Command Format: pwd ?
??

Sample Session:

??
? $pwd ?
? /user0/teacher ?
? $ ?
??

Notice that this is an absolute pathname. This is the pathname
of the current working directory.
4.2 Creating Directories

Directories are created by the following command:

??
? Command Format: mkdir [options] <dirname> ?
? ?
? options - see man pages for a complete list ?
? ?
? dirname - name of the new directory (absolute or ?
? relative pathname). ?
??

If the option to change permission mode is not given, the
directory will have default permissions set to read,write,execute
for the user and read and execute for group and others. The
files . (dot) and .. (dot dot) are created automatically. In
order to create a sub-directory, you must have write permission
on the parent directory. The owner id and the group id are set
to the real users id and group id, respectively.

4.3 Removing Directories

Directories can be deleted using the rmdir command.

??
? Command Format: rmdir [options] <dirname> ?
? ?
? options - see man pages for a complete list ?
? ?
? dirname - the directory to remove, it must be empty. ?
? ?
??

Sample Session:

??
? $pwd ?
? /user0/teacher ?
? $ls -la ?
? total 5 ?
? drwxr-xr-x 2 teacher class 512 Jul 18 08:12 . ?
? drwxrwxr-x 5 root root 2048 Jul 1 13:14 .. ?
? $rmdir teacher ?
? rmdir:teacher:Directory does not exist ?
? $ ?
??

Normally, directories are deleted using the rmdir command.
Before the directory can be removed, it must be empty; that is,
it must not contain any files. Notice that in the above example
two files are present, . (dot) and .. (dot). Remember, these
refer to the current working directory and its parent. They
cannot be removed.
Sample Session:

??
? $rmdir . ?
? rmdir: .: Can't remove current directory or .. ?
? $ ?
??

For the purposes of deleting a directory, the directory is empty
if it contains only two files, namely . (dot) and .. (dot dot).
4.4 Changing Directories

To "move around" in the filesystem, use the cd (change directory)
command.

??
? Command Format: cd [dirname] ?
? ?
? dirname - If not specified, the value of the $HOME ?
? shell variable will be used as the new ?
? current working directory. ?
? ?
? If the directory given is an absolute pathname ?
? that directory is the new current working ?
? directory. A relative pathname can also be ?
? given. ?
??

Sample Session:

??
? $cd /user0/teacher ?
? $pwd ?
? /user0/teacher ?
? $ ?
??

The current working directory is now /user0/teacher.

Sample Session:

??
? $cd memos ?
? $pwd ?
? /user0/teacher/memos ?
? $ ?
??

This command will look for a subdirectory called memos under the
current working directory. If it is found, it will become the
new working directory; otherwise, an error will occur.

Error messages beginning with "cannot access file..." often
indicate that the pathname is incorrect or misspelled.
4.5 Renaming Directories

The mv (move) command can also be used to rename a directory.

??
? Command Format: mv <dirname> <target> ?
? ?
? dirname - name of the source directory ?
? target - target directory name ?
??

Sample Session:

??
? $mv users newusers ?
? $ ?
??

This will have the effect of changing the name of the directory
users into newusers. The permissions on the directory will
remain the same.

NOTE: All files and subdirectories in the directory newusers
now have new absolute pathnames.
4.6 The directories . (dot) and .. (dot dot)

The filename . (dot) represents the current working directory;
and the filename .. (dot dot) represent the directory one level
above the current working directory, often referred to as the
parent directory. If we enter the command to show a listing of
the current working directories files and use the -a option to
list all the files and the -l option provides the long listing,
this is the result.

Sample Session:

??
? $ls -la ?
? total 975 ?
? drwxrwxr-x 4 teacher class 2048 Jul 16 17.56 . ?
? drwxr-xr-x 60 root 1536 Jul 13 14:18 .. ?
? ---------- 1 teacher class 4210 May 1 08:27 .profile ?
? -rwxr-xr-x 1 teacher class 1948 May 12 13:42 memo ?
? $ ?
??

The ls -la command displays access modes, number of links, the
owner, the group, size, etc. of files in a directory; but also
displays the characteristics of the current working directory and
its parent. The first entry is the entry for the current
directory. The owner is teacher and the group is class. The
second entry is the parent directory. It is one level up from
the current working directory. It is owned by the root
directory.

Instead of asking for information on all of the files in a
directory, you can request just the information on the current
working directory.

Sample Session:

??
? $ls -ld ?
? drwxrwxr-x 4 teacher class 2048 Jul 16 17:56 . ?
? $ ?
??

The response from the command simply shows the long information
for the current working directory . (dot).
Information can also be obtained for the parent of the current
working directory by using its name as an argument.

Sample Session:

??
? $ls -ld .. ?
? drwxr-xr-x 60 root root 1536 Jul 13 14:18 .. ?
? $ ?
??

Here's the long list of the current working directories parent.
(.. is the shorthand representation of the current working
directories parent)

Both of the directory names . (dot) and .. (dot dot) can be used
as arguments to commands. To change the parent of the current
working directory into the current working directory, the command
is:

Sample Session:

??
? $pwd ?
? /user0/teacher ?
? $cd .. ?
? $pwd ?
? /user0 ?
? $ ?
??

The current working directory is the former parent.

This is all very interesting but what good is it? You can
specify the current working directory or its parent without
typing the entire absolute pathname. It can also be handy when
giving arguments to UNIX commands.

Why are the pathnames sjones/chem and ./sjones/chem equivalent?
4.7 Directory Access Modes

Directory access modes are listed and organized in the same
manner as any other file. There are a few differences that need
to be mentioned.


4.7.1 Read

Access to a directory means that the user can read the contents.
The user can look at the filenames inside the directory.


4.7.2 Write

Access means that the user can add or delete files to the
contents of the directory.


4.7.3 Execute

Executing a directory doesn't really make a lot of sense so think
of this as a traverse permission. This access allows the user to
reference the directory name in a command. The reference is not
necessarily explicit, since the shell deduces the absolute
pathname of a command from the user's environment. For example,
the shell knows that the full pathname of the ls command is
/bin/ls. A user must have execute access to the bin directory in
order to execute ls.

If traverse permissions are denied, others cannot change to it or
through it. Another user can't do a cd to the protected
directory or any subdirectory beneath it.
IN CLASS QUIZ
?
? / ?
?
?
?
? ? ? ? ?
?? ?? ?? ?? ??
? bin ? ? tmp ? ? etc ? ? mnt ? ? l ? ? dev ?
?? ?? ?? ?? ??
?
??
? ? ? ?
? ?? ?? ??
? Uni1 ? ? Uni2 ? ? Uni3 ? ? Uni4 ?
? ?? ?? ??
{1} ? ? ??
? ?? ? ? ?? ?? ?? ?? ??
? filea ? ? fileb ? ? Dira ? ? filea ? ? Filea ? ? file1 ? ? File2 ? file3 ?{5} ? Dir1 ? ? Dir2 ?
? ?? ? ? ?? ?? ?? ?? ??
? ? ? ? ?
? ? ? ?? ?
? ?? ? ?? ?? ?? ??
? filea ? ? Dirb ? ? fileb ? {2} {3} ? filea ? ? Filea ? }? File1a ? ? file1b ? ? Dir2a ?
? ?? ? ?? ?? ?? ??
? ?
Write the complete pathname for the 5. ________________________________ ?? {7}
files numbered above. {4} ? filea ? ?? ??
6. ________________________________ ?? ? File2aa ? ? file2ab ?
1. _______________________________ 8. You are in /mnni1 and want #1. ?? ??
7. ________________________________
2. _______________________________ ___________________________________

3. _______________________________ Write the minimum pathname needed for 9. You are in /mnni3/File2 and want #4
each of the following:
4. _______________________________ ___________________________________
4.7.4 Typical Root Directory

??
? $ ls -FC / ?
? ?
? ?
? Student/ bin/ lib/ stand/ u2/ user2/ ?
? ?
? Students/ bad/ lisp/ tmp/ unix* usr/ ?
? ?
? Support/ dev/ lost+found/ tmp.sh unix.bak* usr2/ ?
? ?
? etc/ mnt/ tmp1/ unix.test* usr3/ a.out* ?
? ?
? foo rel_notes tmp2/ user0/ install/ shlib/ ?
? ?
? u1/ user1/ ?
??
NOTES
??

Workshop 4

This workshop will reinforce your understanding of the topics
presented in this chapter. Login to the Multimax using the
username and password from the previous workshop. All students
should complete the entire workshop. You may need to work in a
team on the computer exercises.

DESK EXERCISES

1. What is a directory?



2. What is an absolute path name?



3. What is a relative path name?



4. What command will create a directory?



5. What command will remove a directory?



6. What command is used to change from one directory to
another?



7. How would you change the name of a directory?



Continue on the next page
8. What do the files . (dot) and .. (dot dot) represent?




9. What does execute permission on a directory mean?




COMPUTER EXERCISES

10. Login to the Multimax.



11. What is the absolute pathname of your current working
directory? Hint: pwd



12. Type cd etc

What message do you get? Can you explain why?



13. Type cd /etc

What is your current working directory? Why did this
happen?



14. Enter the command that will return you to your home
directory.


Continue on the next page

15. Enter the command that will change to your current working
directories parent.




16. List the contents of your current working directory



17. List the permissions, ownership, size, etc. of your current
directories parent.



18. Enter the command to change to your home directory. Create
a new subdirectory with a name of your choice.



19. Change the current working directory to the subdirectory you
just created.



20. Rename the subdirectory to Student. Is this the same
subdirectory as everyone else in the class? Why?



21. Change to your home directory and delete the subdirectory
Student.



22. Logout of the Multimax and the Annex.
NOTES
??
5. COMMUNICATION UTILITIES

This chapter will deal with the utilities that allow one user to
communicate with another. Some of these utilities require the
other user to be logged in and others do not.

The mail utility can be used to send messages to one or more
users. It is not necessary for the user that is receiving the
message to be logged in. The mail utility delivers the message
to a file belonging to the recipient. The user will be notified
that a mail message exists. Messages can be saved or deleted and
a reply sent.

The talk utility is an interactive session that allows each user
to send message simultaneously to each other. Both users must be
currently logged in for this utility to work.

The write utility is a one-way communication. It allows you to
send a message to another user. The user must be logged in and no
reply is possible.

5.1 Sending Electronic Mail

The basic command line format for sending mail is:

??
? Command Format: mailx [options] [user1[usern]] ?
? ?
? options - see man pages for a complete list ?
? ?
? user1[usern] - one or more users to get the mail ?
? message ?
? ?
??

The username is the name assigned by the system administrator to
a user on the UNIX system (for example, rharding). The username
can also include a system name if the recipient is on another
UNIX system that can communicate with the sender's (for example,
sys2!rharding). Let's assume that the recipient is on the local
UNIX system.

Sample Session:

??
? $mailx rharding(Ret) ?
? Subject: ?
??

Now enter the subject of your message followed by a (Ret). The
cursor will appear on the next line. Simply start typing the
message. There is no limit to the length of a message. When you
have finished, send it by typing Ctrl-D on a new line.

Sample Session:

??
? $mailx rharding(Ret) ?
? Subject: Work schedule(Ret) ?
? Please check the bulletin board(Ret) ?
? for the new work schedule.(Ret) ?
? Ctrl-D ?
? $ ?
??

The shell prompt on the last line indicates that the message has
been queued (placed in a waiting line) and will be sent.
5.2 Reading Mail

To read your mail enter:

Example:

.................................................................
. $mailx .
.................................................................

Executing this command places you in the command mode of mailx.
If there are no mail messages waiting to be read, you will see
the following message on the screen:

Sample Session:

??
? $mailx ?
? No mail for teacher ?
? $ ?
??

Of course, your username will appear instead of 'teacher'.

When a mail message appears in the recipient's mailbox, the
following message will appear on the screen.

Example:

.................................................................
. you have mail .
.................................................................

This notice will appear when you login to the system or upon
return to the shell from another procedure.
When you have been notified of mail waiting to be read, enter the
command to enter mail. The screen will look something like this:

Sample Session:

??
? $mailx ?
? ?
? mailx version 3.1 Type ? for help. ?
? "/usr/mail/teacher": 3 messages 3 new ?
? >N 1 bhood Fri Jul 13 13:01 21/324 Review session?
? N 2 class2 Fri Jul 13 14:53 15/211 Meeting notice?
? N 3 phajny Fri Jul 13 16:53 11/272 Reorganization?
? ? ?
??

This first line indicates the version of mailx that is being
used. In this case, version 3.1. There is a reminder that help
is available by typing the ?. The second line shows the path
name of the file used as input (usually the same as the username)
and a count of the total number of messages and their status.
The messages are numbered in sequence with the latest one
received on the bottom of the list. To the left of the sequence
numbers, there may be a status indicator; N for new, U for
unread. The > symbol points to the current message. The other
fields in the header line show the login of the sender, day,
date, and time it was delivered. The next field has the number
of lines and characters in the message. The last field is the
subject of the message; it might be blank.

To read the mail messages you can do any of the following steps:

(Ret) - This will cause the current message to
be displayed. The current message is
the once indicated by the > sign.

p (Ret) - This is equivalent to pressing the (Ret)
key with no argument. The current
message will be displayed.

p 2 (Ret) - You can press p (for print) or t (for
type) followed by the message number(s).

p teacher (Ret) - This will print all messages from user
teacher.
5.3 Saving Mail

All messages that are not specifically deleted are saved when
quitting mailx. Messages that have been saved are placed in a
file in the home directory called mbox. The mbox file is the
default. It is possible to save them in a file of the users
choice. Messages that have not been read are held in the
mailbox. The command to save messages comes in two forms.

??
? Command Format: S [msglist] ?
? ?
? msglist = ?
? ?
? n message number n the current message ?
? ?
? ^ the first undeleted message ?
? ?
? $ the last message ?
? ?
? * all messages ?
? ?
? n-m an inclusive range of message numbers ?
? ?
? user all messages from user ?
? ?
? /string All messages with string in the subject line ?
? (case is ignored) ?
? ?
? :c all messages of type c where c is: ?
? ?
? d - deleted messages ?
? n - new messages ?
? o - old messages ?
? r - read messages ?
? u - unread messages ?
? ?
??
Messages specified by the msglist argument are saved in a file in
the current directory named for the author of the first message
in the list. If the username 'teacher' sent the message and you
entered:

Sample Session:

??
? ? S * ?
? "teacher" [New file] 11/268 ?
? ? ?
??

The mail message has been saved into a file in your current
directory called 'teacher'. If you want to save the file in
another filename, you can do that with the second method of
saving mail. Basically, it works the same as S; but it allows
you to save the mail to a file you specify.

??
? Command Format: s [msglist] [file1] ?
? ?
? msglist - same arguments as before ?
? ?
? file1 - filename which will receive the saved mail ?
??
5.4 Deleting Mail

To delete a message, enter a d at the command mode prompt
followed by a msglist argument. An msglist argument can be any
one the following:


n message number n the current message

^ the first undeleted message

$ the last message

* all messages

n-m an inclusive range of message numbers

user all messages from user

/string All messages with string in the subject line (case
is ignored)

:c all messages of type c where c is:

d - deleted messages
n - new messages
o - old messages
r - read messages
u - unread messages

For example, suppose you wanted to delete all of your mail
messages. Enter the following command at the command mode
prompt. The command mode prompt for mailx is the question mark
(?).

Sample Session:

??
? $mailx ?
? ?
? mailx version 3.1 Type ? for help. ?
? "/usr/mail/teacher": 3 messages 3 new ?
? >N 1 bhood Fri Jul 13 13:01 21/324 Review session ?
? N 2 class2 Fri Jul 13 14:53 15/211 Meeting notice ?
? N 3 phajny Fri Jul 13 16:53 11/272 Reorganization ?
? ? d * ?
? ? q ?
? $ ?
??

All of the messages have now been deleted. The messages are not
actually deleted until the mailbox is exited. Until that happens
the u (for undelete) command is available. Once the quit command
(q) is entered, however, the deleted messages are gone.
5.5 Undeliverable Mail

If there has been an error in the recipient's username, the mail
command will not be able to deliver the message. For example,
let's say you misspelled the username. It will return the mail
in a message that includes the system name and username of the
sender and recipient. It also includes a message stating the
reason for the failure.

The sender of the message would get a message from mailx
indicating that an error had occurred.

Sample Session:


? $mailx ?
? ?
? mailx version 3.1 Type ? for help. ?
? "/usr/mail/teacher": 1 message 1 new ?
? >N 1 teacher Fri Jul 13 13:45 25/655 Returned mail:User unkno?
? ? ?
? Message 1: ?
? From teacher Fri Jul 13 13:45:57 1990 ?
? Received: by domax1.UUCP (5.51/) ?
? id AA01997; Fri, 13 Jul 90 13:45:54 mdt ?
? Date: Fri, 13 Jul 90 13:45:54 mdt ?
? From: Mail Delivery Subsystem <MAILER-DAEMON> ?
? Subject: Returned mail: User unknown ?
? Message-Id: <[email protected]> ?
? To: teacher ?
? Status: R ?
? ?
? ----- Transcript of session follows ----- ?
? 550 snoopy... User unknown: No such file or directory ?
? ?
? ----- Unsent message follows ----- ?
? Received: by domax1.UUCP (5.51/) ?
? id AA01995; Fri, 13 Jul 90 13:45:54 mdt ?
? Date: Fri, 13 Jul 90 13:45:54 mdt ?
? From: Teacher Account D-7130 <teacher> ?
? Message-Id: <[email protected]> ?
? To: snoopy ?
? Subject: Meeting notice ?
? ?
? Meeting will be held at Charlie Brown's house. ?
? July 13, 1990 ?
? 7:30 p.m. ?
? ?
? ? ?


The ? is the mailx command mode prompt. Mailx is asking for
input.

A list of commands available can be shown by entering a ?.

Sample Session:


? ? ? ?
? mailx commands ?
? type [msglist] print messages ?
? next goto and type next message ?
? edit [msglist] edit messages ?
? from [msglist] give header lines of messages ?
? delete [msglist] delete messages ?
? undelete [msglist] restore deleted messages ?
? save [msglist] file append messages to file ?
? reply [message] reply to message, including all recipients ?
? Reply [msglist] reply to the authors of the messages ?
? preserve [msglist] preserve messages in mailbox ?
? mail user mail to specific user ?
? quit quit, preserving unread messages ?
? xit quit, preserving all messages ?
? header print page of active message headers ?
? ! shell escape ?
? cd [directory] chdir to directory or home if none given ?
? list list all commands (no explanations) ?
? top [msglist] print top 5 lines of messages ?
? z [-] display next [last] page of 10 headers ?
? ?
? [msglist] is optional and specifies messages by number, author, ?
? or type. ?
? The default is the current message. ?
? ? ?


This is a partial list of mailx commands available to you. We
will not discuss all of them. If you are interested in the other
features, you can use the on-line manual pages to find out how to
use them.
5.6 Talk Utility

Talk is a visual communication program which copies lines from
one terminal to that of another user. This is similar to the
phone utility on VMS. Once communication is established between
two users, they can both type simultaneously with their output
appearing in separate windows.


? Command Format: talk <user1> [ttyname] ?
? ?
? user1 - If you are talking to someone on the same machine, ?
? then this is just the person's username. If ?
? you want to talk to a user on another host, then ?
? user1 is of the form: ?
? ?
? host!user or ?
? host.user or ?
? host:user or ?
? user@host ?
? ?
? user@host being preferred ?
? ?
? ttyname - If the person you want to talk to is logged on ?
? more than once, you can use the ttyname argument ?
? to indicate the terminal name. ?


For illustration, let's assume we want to talk with the user
student on the same machine. The command is:

Example originator:

.................................................................
. $talk student .
.................................................................

Example recipient:

.................................................................
. Message from Talk_Daemon@domax1 at 17:36 ... .
. talk: connection requested by teacher@domax1. .
. talk: respond with: talk teacher@domax1 .
.................................................................
When the recipient has typed in talk teacher@domax1, the
following message will appear on the originators screen:

Sample Session originator:

??
? Connection established. ?
??

The screen will be divided in half by a row of dash characters.
The originator will type a message on the top half, and the same
message will appear on the lower half of the screen on the
recipient's screen.

Likewise, everything the recipient types on the top of his screen
the same message will appear on the bottom of the originators
screen. Once this communication is established, the parties may
type simultaneously with their output appearing in different
windows. While in talk, Ctrl-L will cause the screen to be
reprinted, and the erase and kill characters work as you would
expect.

Sample Session originator:

??
? Hi Snoopy, ?
? Charlie Brown suggests we meet at noon today. ?
? ?
? ?
? ?
? ?
? ?
? ?
?-------------------------------------------------------------- ?
? OK, but the billiard championship is in my house at 1 P.M. ?
? ?
? ?
? ?
? ?
? ?
? ?
??
Sample session recipient:

??
? OK, but the billiard championship is in my house at 1 P.M. ?
? ?
? ?
? ?
? ?
? ?
? ?
? ?
?-------------------------------------------------------------- ?
? Hi Snoopy, ?
? Charlie Brown suggests we meet at noon today. ?
? ?
? ?
? ?
? ?
? ?
??

When the communication is finished, the interrupt character will
cause the talk utility to exit.

Example:

.................................................................
. [Connection closing. Exiting] .
.................................................................
5.7 Talk Permission Denied

If you don't wish to have your work interrupted by a request to
establish a talk connection, you can deny messages.

??
? Command Format: mesg [-[n][y]] ?
? ?
? n - no, forbids messages via write by revoking non-user ?
? write permission on the user's terminal. ?
? ?
? y - yes, reinstates permission ?
? ?
? ?
? mesg with no arguments will report the current state ?
? without changing it. ?
??

Sample Session:

??
? $mesg ?
? is y ?
? $mesg -n ?
? $mesg ?
? is n ?
? $mesg -y ?
? $mesg ?
? is y ?
? $ ?
??

The default permission is enabled. Some UNIX commands, however,
disallow messages in order to prevent messy output.
5.8 Write Utility

This command will write a message to the screen of another user.

??
? Command Format: write <user1> [ttyname] ?
? ?
? user1 - username of the user ?
? ?
? ttyname - which terminal to send (i.e. tty00) ?
??

Sample Session originator:

??
? $write lucy ?
? Hello Lucy, ?
? What's the latest from the Psychology Department? ?
? (interrupt character) ?
? $ ?
??

Sample Session recipient:


? $ ?
? ?
? Message from teacher on domax1 (rt021d0) [ Thu Jul 19 13:43:12 ] .. ?
? Hello Lucy, ?
? What's the latest from the Psychology Department? ?
? <EOT> ?
? ?
? $ ?


Here's a suggestion for using write to communicate a little
easier.

When the user first 'writes' to another user, wait for the
recipient to 'write' back before starting to send. Both users
should agree on a signal to indicate to the other person that
they can reply. How about 'o' for over. The signal 'oo' could
be used for "over and out," which would mean that the
communication is finished.
NOTES
??
Workshop 5

This workshop will reinforce your understanding of the topics
covered in this chapter. Login to the Multimax with the username
and password given to you by the instructor. Each student is to
complete the entire workshop. Computer exercises might need to
be worked as a team.

DESK EXERCISES

1. What is the command to send an electronic mail message to
another user on the Multimax?



2. Once you have entered the mail utility what command can you
enter to get help?



3. What does the command d 5-9 accomplish?



4. What is the command to exit the mail utility and return to
the UNIX system prompt?



5. What is the mailx command mode prompt?



6. How would you create a "talk" session to user Student2 on
the host domax0?



7. What time does the billiard championship start?

Continue on the next page

8. What UNIX command will prevent interruption of your work by
someone wishing to "talk"?



9. Regarding "write", does the recipient need to be logged in?



Regarding "talk", does the recipient need to be logged in?

























Continue on the next page
COMPUTER EXERCISES

10. Login to the Multimax.



11. Send a mail message to another student in the class.



How can you find out who is logged in? (who?)



Does the recipient need to be logged in?




12. Send a mail message to username lucy. (lucy does not exist)

What happened? Why?




13. Read your mail and save one message to the current working
directory.

Delete all other mail messages.








Continue on the next page
14. Establish a talk connection with another student.



15. What UNIX command do you enter to deny permission for a talk
connection? Try it!



16. Send a message to another student using the write command.

How is this different from "talk?"



17. Logout of the Multimax and the Annex.

6. SHELL BASICS

There have been several shells written for UNIX. They have
different features and each is in use through out the world. The
BourneShell is the accepted standard for System V UNIX. Another
shell is called the Cshell, named for "C" which is the high-level
programming language. Another shell is the KornShell; it is
named after the person who developed it, David Korn. It has more
features than the BourneShell and is of special interest to
programmers.

The purpose of this chapter is to give you some idea as to the
functions available through the shells and their general
function. Details of shell programming are discussed in another
class, "UNIX Bourne Shell Programming".

UMAX makes full use of the ASCII character set. Unlike operating
system command languages like VMS or NOS, UNIX is case sensitive.
In addition, several characters have special meanings to the
shell. We have already seen that a slash (/) by itself indicates
the root directory and is used with directory, subdirectory, and
filenames to indicate an absolute or relative pathname.

Other special characters that have meaning to the shell include:

` ' $ { } || && ;

Input to a command is usually taken from your keyboard, and the
output of a command is normally displayed on your monitor screen.
Keyboard input is referred to as "standard input" or "stdin," and
screen output as "standard output" or "stdout."
6.1 Input Redirection

It is possible to instruct UNIX to get data from a file rather
than from the keyboard. This is called input redirection. To
indicate that input to a command is to come from a file rather
than the keyboard, use the input redirection character (<).

??
? Command Format: command < input-file1 ?
? ?
? command - a command ?
? ?
? input-file1 - input file that supplies input ?
? to the command ?
??

A Memory Trick: The less-than symbol looks like a funnel. If
you pour liquid into the wide end, it flows
to the narrow end. The input-file "pours"
its contents into the command.

Sample Session:

??
? $mailx phajny < report ?
? $ ?
??

The file named report will be sent to the login name phajny.
Mail normally expects the input to come from standard input, the
keyboard. The input redirection symbol causes the input to mail
to come from the file called report.
6.2 Output Redirection

It is also possible to instruct UNIX to send data to a file
rather than sending it to the default monitor screen. This is
called output redirection. To indicate that the output from a
command is to go into a file rather than be displayed on the
monitor screen, use the output redirection character >.

??
? Command Format: command > output-file1 ?
? ?
? command - a command ?
? ?
? output-file1 - output file that will receive the output ?
? from the command ?
??

The memory trick still works; only now the funnel points toward
the file that will receive the output.

Sample Session:

??
? $ls -l > listing ?
? $ ?
??

The output of the ls command will not be displayed on the screen,
instead it will be in the file named listing. If the file does
not exist, the shell will create it. If it already exists, it
will be overwritten.

WARNING: The shell will NOT issue a warning about overwriting
the original file.

It is possible to use the cat command to create a file and input
text into that file using output redirection. The following
example shows how this can be done.

Sample session:

??
? $cat > file1 ?
? This is a line of text. ?
? This is another line of text. ?
? (Ctrl-D) ?
? $cat file1 ?
? This is a line of text. ?
? This is another line of text. ?
? $ ?
??
6.3 Output Redirection with Append

The following shell command will also redirect the output to a
file but instead of overwriting the existing file, it will append
the output to the end of output-file.

??
? Command Format: command >> output-file1 ?
? ?
? command - a command ?
? ?
? output-file1 - receives the output from command ?
??

Believe it or not, the memory trick still works; only in this
case, one funnel feeds onto another. So the output is fed onto
the end of output-file. Okay, it's a little far fetched; but it
can help you remember. Try it.

Sample Session:

??
? $ls -l subdir >> listing ?
? $ ?
??

This will append the output of the ls command to the file listing
without destroying any existing data. If the file does not
exist, the shell will create it.

Again, it's possible to append text to the end of an existing
file using the cat command. Note the following example.

??
? $cat >> file1 ?
? This is a third line of text. ?
? This is a fourth line of text. ?
? (Ctrl-D) ?
? $cat file1 ?
? This is a line of text. ?
? This is another line of text. ?
? This is a third line of text. ?
? This is a fourth line of text. ?
? $ ?
??

If the file does not exist it will be created and the text added.

6.4 Input and Output Redirection

Input and output redirection can occur on the same command line.

??
? Command Format: command < input-file1 > output-file1 ?
? ?
? command - A command ?
? input-file1 - supplies input to command ?
? output-file1 - receives the output from command ?
??

Sample Session:


? $cat command_file ?
? p ?
? $mailx < command_file > result_file ?
? ?
? $cat result_file ?
? mailx version 3.1 Type ? for help. ?
? "/usr/mail/teacher": 1 message 1 new ?
? >N 1 teacher Mon Dec 31 10:16 57/3171 ?
? Message 1: ?
? From teacher Mon Dec 31 10:16:30 1990 ?
? Received: by domax1.UUCP (5.51/) ?
? id AA18976; Mon, 31 Dec 90 10:16:28 mst ?
? Date: Mon, 31 Dec 90 10:16:28 mst ?
? From: Teacher Account D-7130 <teacher> ?
? Message-Id: <[email protected]> ?
? To: teacher ?
? Status: R ?
? ?
? What's Happening ?
? by Pam Hajny ?
? Denver Office ?
? ?
? With IRM Training: ?
? ?
? A Reclamation-wide workshop was held in early October to discuss information ?
? resources management training. Trainers from each region and the Denver Offic?
? shared training techniques, ideas and course materials. We met one afternoon ?
? with the personnel training officers to discuss broad IRM training needs and ?
. .
. .
. .

6.5 Pipes

The output of a command can be used as the input to a second
command by using the "pipe" symbol (|) without using any
temporary files. On some terminals the pipe symbol is a vertical
bar and on others it is a broken vertical bar. Both will work
exactly the same. The following command format shows how to use
the pipe symbol:

??
? Command Format: command1 | command2 ?
? ?
? command1 - a command ?
? ?
? command2 - a second command ?
??

Example:

.................................................................
. $man acct | pg .
.................................................................

The output from the command man are processed by the pg command
before appearing on your screen. Normally the output from the
man command will appear on the monitor line after line until the
end is reached. In this case, the output is "piped" to the pg
command; and the screen will stop scrolling after 23 lines so you
can read them.
6.6 Wildcards

Wildcards are special characters that cause the shell to search
over a range of possible values.

? represents any one character, while

* stands for any number of characters including none.

Example:
jo?eph

This indicates that the third letter of the string "jo eph" could
be any single character. Any character could be substituted for
the ? character, including numeric and special characters.

To limit the range of possible values, enclose the possibilities
in brackets [ ].

Example:
jo[a-z]eph

This example limits the range of characters to the set lowercase
a through lowercase z. Uppercase characters, numeric, or special
characters would not make a match. Notice that only one charater
will make a match.

Using a comma as a separator between choices we can further
restrict the range.

Example:
jo[s,m,5]eph

The only set of characters that will make a match are lowercase
s, lowercase m, and the number 5. No other character will make a
match.

The string jos* causes the shell to look for every string that
begins with the letters "jos," regardless of their length while
[i-k]*h finds every string that begins with "i", "j", or "k" and
ends with an "h".






Wildcards are extremely useful in wide variety of applications.
For example, if you want to use the man pages, but do not know
the exact command names on the subject of system accounting, try

Sample Session:

.................................................................
. $man acc* .
.................................................................

All of the commands that begin with the letters acc followed by
any string (including none) will be passed to the man command as
arguments.

If you wanted to get a listing of all the files in your current
working directory that ended in .c (these are the C source code
programs). You could enter the following command:

Sample Session:

.................................................................
. $ls *.c .
.................................................................
In order for the shell to stop interpretation of a special
character (i.e., use it as a normal character), it must be
preceded by a backslash (\) or enclosed in single quotes.

Example:
jo\?eph
or
'jo?eph'

Both of these examples represent the string jo?eph. The shell
will not interpret the question mark character as a wildcard
metacharacter.

6.7 Reestablishing a Background Job

Processes in UNIX can run in the foreground or the background.
Foreground processes are interactive; the input is read from the
keyboard or standard in, and the out goes to the monitor screen
or standard out. Background jobs run with no interaction with an
interactive terminal. Your current interactive process can be
suspended by typing the break character at the shell prompt.

Sample Session:

??
? $ <break> ?
? annex: ?
??

The jobs command displays information on all current jobs
(sessions). The most recent job is marked with a plus sign (+),
and the next previous is marked with a dash or minus sign (-). A
job begins when you execute a command to connect to a host (or
another Annex). A job ends when you logout from the host or
terminate the job at the Annex with the kill or hangup command.

The number of possible jobs allowed per user is determined by the
network administrator. The number of jobs can range from 1 to 16
with a default of 3.
The Annex command to display the information about the current
job(s) is:

??
? Command Format: jobs ?
??

If there are no jobs, the annex: prompt will be displayed. If
there are some 'suspended' jobs the following will appear:

Sample Session:

??
? annex: jobs ?
? +1 rlogin domax1 ?
? -2 rlogin domax1 ?
? annex: ?
??

This shows that there are two jobs in suspension. Both of these
sessions did a remote login to domax1. This is just for
illustration.
The fg (foreground) command returns to a suspended job. The
command displays the job number and the Annex command that
created it. When no arguments are provided, fg will return to
the most recent job. With a numeric argument, fg returns the
specified job.

To connect with a suspended job (session) enter the following
Annex command:

??
? Command Format: fg [n] ?
? ?
? (none) - most recent job (+) to foreground ?
? n - job "n" to foreground ?
??

Sample Session:

??
? annex: jobs ?
? +1 rlogin domax1 ?
? -2 rlogin domax1 ?
? annex:fg 1 ?
? 1 rlogin domax1 ?
? (Ret) ?
? $ ?
??
NOTES
??
Workshop 6

This workshop will reinforce your understanding of the topics
covered in this chapter. Login to the Multimax with the username
and password given to you by the instructor. Each student is to
complete the entire workshop. Computer exercises might need to
be worked as a team.

DESK EXERCISES

1. What is the meaning of the term "case sensitive?"



2. What is a wildcard?



3. How does the shell interpret the following wildcards?

a. ?

b. [0-9]

c. *


4. How does the shell interpret the following strings?

a. M[i,r]*

b. b?ll

c. me??[1,2]

d. '*special*'

e. anyone\?


Continue on the next page
5. What is "standard input?"




6. What symbol causes a command to take its input from a file?




7. What is "standard output?"



8. What symbol causes the output of a command to be redirected
to a file?




9. What symbol causes the output of a command to be redirected
to the input of another command?




10. What symbol is used to indicate input is to be from a file
instead of the keyboard?




11. How can the output from a command be saved in an ordinary
file?



Continue on the next page
12. What is a pipe? No, it's not something you smoke.



COMPUTER EXERCISES

13. Login to the Multimax



14. How many different on-line manual entries are displayed by
executing the command man ca*?




15. Execute man ls | pg. What is the purpose of the |
character?



16. Save the on-line manual pages on the cat command in a file
called mp0. (hint: output redirection)



17. Save the on-line manual pages on the assist command in a
file called mp1. (no hint this time)



18. Type cp mp0 man

Does file mp0 still exist after this command is executed?

Why?


Continue on the next page
19. Type mv mp1 assist

Does file mp1 still exist after this command is executed?

Why?



20. Type cp mp3 man

What error message do you get?



21. Logout of the Multimax and the Annex.
7. UMAX FILE TRANSFER PROTOCOL (FTP)

File Transfer Protocol (FTP) is a utility which can transfer
files to and from TCP/IP networked computers. TCP/IP stands for
Transmission Control Protocol/Internet Protocol and consists of a
suite of defacto standard protocols for networking computers.
FTP is one protocol in that suite. (Other significant protocols
within TCP/IP are TELNET, Simple Mail Transfer Protocol (SMTP),
and Network File Systems (NFS).) The Client portion of UNIX FTP
lets users on the Multimax access file systems on a remote
computer. The Server portion of UNIX FTP lets users on remote
computers access Multimax files. For Reclamation, these remote
computers would be VAXes, CYBERs, IBMs, and Sun workstations.

Using FTP, you can access directories and files on a remote
computer and perform common operations, such as list and change
working directories, transfer files, create directories, delete
working directories, delete files and directories, and rename
files and directories. Once you have entered the FTP utility,
you make a connection to the desired remote computer and then
work with the remote computer's files using FTP commands. The
connection to the remote computer's FTP remains in effect until
terminated by the user. Multimax FTP supports both local help
for FTP commands and remote help, which displays FTP elements
available on the remote computer.

Throughout this chapter, the term "local computer" will refer to
the Multimax. The term "remote computer" will refer to the CYBER
mainframe or the VAX minicomputer. Please be aware that these
procedures will work for any computer connected to the Ethernet
that has an FTP server installed. The messages that appear may
be different, but the process will be the same.
7.1 Initializing FTP on UMAX

FTP can be invoked on the Multimax using the following syntax:

??
? ?
? Command Format: ftp [options] [host] ?
? ?
? options - see man pages for a complete list ?
? ?
? host - the name of the remote computer ?
? ?
??

NOTE: UNIX is case sensitive. The commands and options must
be entered as shown.
7.2 Establishing Connection with the Remote Computer

There are two ways to make a connection with the remote computer.

7.2.1 Calling FTP with no hostname

The first way is to invoke FTP using no options, simply enter the
ftp command at the shell prompt. UMAX will respond with the ftp
prompt: ftp>

Sample Session:

??
? $ftp ?
? ftp> ?
??

FTP commands can now be entered. The utility has its own set of
commands, and we will discuss about 12 of them in this chapter.
A complete list of the FTP commands can be obtained by entering
help at the FTP prompt.

The command to establish a connection with remote computer is:

??
? ?
? Command Format: open <host> [port] ?
? ?
? host - hostname, this host must have an FTP server. ?
? ?
? port - port number (optional) ?
? ?
??

This command will establish a connection to the remote computer's
FTP server. The hostname for the VAX is ERC830. The following
FTP command will establish a connection with the VAX (ERC830):

VAX Sample Session:

??
? ftp>open erc830 ?
? Connected to erc830. ?
? 220 erc830 Wollongong FTP Server (Version 5.0) at Mon Dec 4 ?
? Name (ERC830:rharding): ?
??
The cursor will stop after the colon. FTP is waiting for you to
enter the login name to use when signing on to the remote
computer. FTP tries to help you out by giving you a default
login name. In the above example, the default login name is
rharding. To select the default name, press (Ret). You can
enter any login name you want and then press (Ret). After you
have selected the login name, either by choosing the default or
entering a new name, you will be asked for the password.

VAX Sample Session:

??
? 331 Password required for rharding. ?
? Password: ?
? 230 User logged in, default directory D_1131:[RHARDING] ?
??

Enter the password required for the login name that you
specified. Echoing is disabled and the password you enter will
not be displayed on the screen. If you entered the correct
password, message number 230 will show you are logged in and the
default directory on the remote system. You are now logged into
the remote computer system and can proceed to transfer files.

CYBER Sample Session:

??
? $ftp ?
? ftp>open cy2 ?
? Connected to cy2. ?
? 220 SERVICE READY FOR NEW USER. ?
? Name (cy2:rharding): class8 ?
? 331 USER NAME OKAY, NEED PASSWORD. ?
? Password: secret ?
? 230 USER LOGGED IN, PROCEED. ?
? ftp> ?
??

This example for the CYBER is similar to the VAX example. Notice
that there a few differences. The login name was changed from
rharding and the username class8 was entered instead.
7.2.2 Calling FTP with a hostname

The second method of signing on to the remote computer is to
specify the name of the remote computer on the call to ftp.

VAX Sample Session:

??
? $ftp erc830 ?
? 220 erc830 Wollongong FTP Server (Version 5.0) at Fri Dec ?
? Name (ERC830:rharding): ?
??
You can now enter the username for the remote system, and you
will then be prompted for the password. The effect of specifying
the hostname on the ftp command line is to do an "automatic" open
command.

NOTE: The messages are slightly different from the VAX login.
The login for the CYBER works in a similar manner.
7.3 Local Computer Commands

From the FTP prompt, you can issue commands to the local computer
to display files or show the contents of a directory. The
commands you enter are FTP commands; and although they might
resemble UNIX commands, they are NOT UNIX commands.

The FTP command to transfer file(s) from the remote computer to
the local computer is as follows:

??
? ?
? Command Format: get <remote-file> [local-file] ?
? ?
? remote-file - the filename on the remote computer ?
? ?
? local-file - the filename on the local computer ?
? ?
??

This FTP command will retrieve the remote-file and store it on
the Multimax. If the local-file name is not specified, the name
of the file on the Multimax will be the same as it was on the
remote computer. The current settings for type, form, mode, and
structure will be used during the file transfer.

VAX Sample Session:

??
? ftp>get overview.dat ?
? 200 PORT Command OK. ?
? 125 File transfer started correctly ?
? 226 File transfer completed ok ?
? local: overview.dat remote: overview.dat ?
? 884 bytes received in 0.04 seconds (22 Kbytes/s) ?
? ftp> ?
??

Messages 200, 125, and 226 let you know that the file transferred
properly. The next line shows the local-filename, in this case
we didn't specify the local-filename, so the remote-filename and
the local-filename are the same. The next line shows the number
of bytes transferred and the amount of time it took to transfer
the file.
CYBER Sample Session:

??
? ftp>get prolog8 ?
? 220 COMMAND OKAY. ?
? 150 FILE STATUS OKAY; ABOUT TO OPEN DATA CONNECTION. ?
? 226 CLOSING DATA CONNECTION. ?
? local: prolog8 remote: prolog8 ?
? 41 bytes received in 0.8 seconds (0.05 Kbytes/s) ?
? ftp> ?
??
7.3.1 Changing the Local Directory

The directory on the local computer can be changed to any
directory you desire. This is called the working directory.
This is the directory where files that are transferred from the
remote computer will be stored.

The syntax of the command to change local working directory is as
follows:

??
? ?
? Command Format: lcd [dirname] ?
? ?
? dirname - the name of the new local working directory ?
? ?
? if directory is omitted, the home directory is assumed ?
? ?
??

Sample Session:

??
? ftp>lcd /user0/student0 ?
? Local directory now /user0/student0 ?
? ftp> ?
??

Absolute or relative pathnames can be specified for directory.
7.3.2 Listing the Contents

Any UNIX command can be entered from the FTP utility. You must
preface the command with the FTP command that invokes the
interactive shell.

The syntax to invoke the interactive shell is as follows:

??
? ?
? Command Format: ! [command [arguments]] ?
? ?
? command - any valid UNIX command, if omitted the ?
? interactive shell is invoked ?
? ?
? arguments - if supplied are arguments to the UNIX command ?
? ?
??

If arguments are provided, the first argument is considered to be
the UNIX command and the remaining arguments are considered to be
arguments to that command.

Example:

.................................................................
. ftp>!ls -la .
.................................................................

This command will display the contents of the local working
directory. The l option specifies the 'long' listing, and the a
option requests all files including the initialization files.
7.4 Remote Computer Commands

From the FTP prompt, you can issue commands to the remote
computer to display files or show the contents of the remote
directory. Recall that the commands you enter are FTP commands;
and although they look like UNIX commands, they are not.

Transferring file(s) from the Multimax to the remote computer is
accomplished with the following command:

??
? ?
? Command Format: put <local-file> [remote-file] ?
? ?
? local-file - the filename on the local computer ?
? ?
? remote-file - the filename on the remote computer ?
? ?
??

This FTP command will retrieve the local-file, transfer it to the
remote computer, and store it in the remote directory. If the
remote-file is not specified, the name of the file on the remote
computer will be the same as it was on the Multimax. The current
settings for type, form, mode, and structure will be used during
the file transfer.