The following is an explanation of the most useful commands.
 

          cd
         chmod
         clear
         cp
         emacs
         finger
         ls
         mkdir
         more
         mv
         pwd
         rm
         rmdir
         telnet
         whoami          
 
 

Changes the current working directory to dirName, or to the home directory if dirName is not given.

Changes the permissions of each given file according to mode, which can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new permissions.

Options

-c, --changes
            Print information about files that are affected.
-f, --silent, --quiet
            Do not notify user of files that chmod cannot change.
-v, --verbose
            Print information about each file, whether changed or not.
-R, --recursive
            Traverse sub directories recursively, applying changes.
 

Who
u    User
g    Group
o    Other
a    All (default)

Opcode
+    Add permission
-     Remove Permission
=    Assign permission (and remove permission of the unspecified fields)

Permission
r             Read
w           Write
x            Execute
s            Set user (or group) ID
u            User's Present Permission
g            Group's Present Permission
o            Other's Present Permission
l            Mandatory locking

You can also specify permissions by a three-digit octal number.  The first digit designates owner permission, the second, group permission and the third other's permission.
Permissions are calculated using the following octal values:

        4        Read
        2        Write
        1        Execute

Examples:

chmod u+x file      -Add execute by user in the permissions of file.

chmod 751 file        -Let owner be able to read, write, and execute
                                   Group is able to read and execute and
                                    Other's is only able to execute the given file.

Clear the terminal display

       cp [options] source dest
       cp [options] source... directory
 
  If the last argument
       names an existing directory, cp copies each other given file into  a  file
       with  the  same  name in that directory.  Otherwise, if only two files are
       given, it copies the first onto the second.  It is an error  if  the  last
       argument  is  not  a  directory  and  more  than  two files are given.  By
       default, it does not copy directories.

   OPTIONS
       -a, --archive
              Preserve as much as possible of the structure and attributes of the
              original files in the copy.  The same as -dpR.

       -b, --backup
              Make  backups of files that are about to be overwritten or removed.

       -d, --no-dereference
              Copy symbolic links as symbolic links rather than copying the files
              that  they  point  to, and preserve hard link relationships between
              source files in the copies.

       -f, --force
              Remove existing destination files.

       -i, --interactive
              Prompt whether to overwrite existing regular destination files.

       -l, --link
              Make hard links instead of copies of non-directories.

       -P, --parents
              Form the name of each destination file by appending to  the  target
              directory  a  slash and the specified name of the source file.  The
              last argument given to cp must be the name of  an  existing  direc-
              tory.   For  example, the command `cp --parents a/b/c existing_dir'
              copies the file a/b/c to existing_dir/a/b/c, creating  any  missing
              intermediate directories.

       -p, --preserve
              Preserve  the original files' owner, group, permissions, and times-
              tamps. -r     Copy directories recursively, copying  all  non-directories  as  if
              they were regular files.
 
 

A text editor and all-purpose work environment.

For more information, refer to the man pages by typing "man emacs" in your xterm window.

Display data about one or more users, including information listed in the files .plan and .project in each user's home directory.  You can specify each user either as a login name (exact match) or as a first or last name.  Networked environments recognize arguments of the form user@host and @host.

Options

    -l        Force long format (default)

    -m      Suppress matching of users "real" names.

    -p       Omit .plan and .project file from display

    -s       Show short format

Lists the contents of directories.  If no names are given then lists the files in the current directory.  With one or more names, list files contained in directory name or that match a file name.  names include filename metacharacters.  The options let you display a variety of information in different formats.

Options-
    -l , --format =single-column
                Print one entry per line of output

    -a        List all files, including the normally hidden files whose names begin with a period.

    -s, --size
                Print size of the files in blocks

    -B, --ignore-backups
                Do not list files ending in '~' , unless given as arguments.

    -R,--recursive
                Recursively list sub directories as well as the specified(or current) directory.

mkdir [options] directories

Create one or more directories.

Options
       -p, --parents
                Create intervening parent directories if they do not exist.

Examples:
    mkdir foo
                 -places a directory "foo" in the current directory

    mkdir -p work/junk/questions
                - creates intervening parent directories.

 
 More is a filter for paging through text one screenful at a time.  This
 version is especially primitve.  Users should realize that less(1) pro-
 vides more(1) emulation and extensive enhancements.
 

Move or rename files and directories.  The source and target determine the result.

Source             Target                       Result
File                  name                         Rename file as name.
File                  Existing File            Overwrite existing file with source file.
Directory        name                         Rename directory as name.
Directory        Existing directory    Move directory to be a sub directory
                                           ;                 of existing directory.
One or             Existing Directory    Move files to a directory.
more files

Options
       -b, --backup
                Backup files before removing.
 
 

Print the full path name of the current working directory

Remote login.  rlogin connects the terminal on the current local host system to the remote host system rhost.  The remote terminal type is the same as your local terminal type.

Options-
    -l user name
            Specify a different user name for the remote login.  Default is the same as your local user name.

removes the specified file from the directed.

removes the specified directory

The telnet command is used for interactive communication with another
 host using the TELNET protocol. It begins in command mode, where it
 prints a telnet prompt ("telnet> "). If telnet is invoked with a host ar-
 gument, it performs an open command implicitly.
 

Print current user ID.