2 Overview of the DIGITAL UNIX User Environment

Using a DIGITAL UNIX operating system is similar to using an ULTRIX and UWS operating system. Like an ULTRIX and UWS system, a DIGITAL UNIX system offers both a windowing graphical user interface (GUI) for workstations and a terminal interface.

Also like ULTRIX and UWS, the DIGITAL UNIX workstation interface is DECwindows, based on the industry standard OSF/Motif. As a result, there are no significant differences between the workstation interfaces of both systems. ULTRIX and UWS does offer, in addition, an XUI version of the DECwindows interface, based on a DIGITAL proprietary graphical user interface.

In addition to the windowing interface, you can use the DIGITAL UNIX system from a terminal or from a workstation window that emulates a terminal. With few exceptions, the commands and tools you use on an ULTRIX system are on the DIGITAL UNIX system. DIGITAL UNIX command and file names are case sensitive, just as they are on the ULTRIX system. You can use pipes, command input and output redirection, and background jobs in the same way that you use these features on an ULTRIX system.

This chapter gives an overview of the DIGITAL UNIX user environment, including differences in the workstation environment, differences in the DIGITAL UNIX directory structure, and differences in supported tools and shells, and differences in the security environment.

Note

For details about using a DIGITAL UNIX system, see the DECwindows User's Guide and the Command and Shell User's Guide.

2.1 Differences in the DIGITAL UNIX DECwindows Interface

The DIGITAL UNIX DECwindows interface is based on OSF/Motif Version 1.2.3. By contrast, ULTRIX and UWS gives you a choice of two DECwindows interfaces: OSF/Motif and XUI. The OSF/Motif interface is almost identical to the DIGITAL UNIX system interface, because the ULTRIX and UWS implementation is based on OSF/Motif Version 1.2.2. The ULTRIX and UWS XUI interface is based on the DIGITAL developed graphical user interface.

2.2 Differences in the DIGITAL UNIX Directory Structure

The directory structure on your DIGITAL UNIX system is different from the directory structure on an ULTRIX system. Figure 2-1 shows most of the directories in the root ( / ) file system.

Figure 2-1: DIGITAL UNIX Directory Structure for General Users

As the figure shows, the directory structure on DIGITAL UNIX is identical to the ULTRIX directory structure in many ways. (This figure does not show the complete directory structure; for example, the /opt, /dev, and /mnt directories, which are typically not used by general users, are omitted. See also Section 4.8.1.) The following list describes important differences:

Some commands that are in /bin on an ULTRIX system are in the /usr/bin or /usr/sbin directory on a DIGITAL UNIX system. This change should not affect you because your PATH environment variable causes the DIGITAL UNIX system to search the appropriate directories for commands. As a start, you can use the same definition for the PATH environment variable as you used on the ULTRIX system. However, you should remove /bin from your path definition and add /usr/bin and /usr/sbin.
If you need to determine the location of a particular command that is not in your path, you can use the whereis command, which looks for commands in a set of standard locations. If a given command file is in more than one directory, whereis reports all locations of the command.

The DIGITAL UNIX directory structure contains the /home directory. On DIGITAL UNIX systems, this directory is intended to be used to contain the home directories for users. For example, the home directory for a user named Ross might be /home/ross. See your system administrator for the actual location of your home directory.

The DIGITAL UNIX directory structure contains the /sbin and /usr/sbin directories. The /sbin directory contains commands that system administrators use when the system is in single-user mode; /usr/sbin contains commands administrators use in multiuser mode.

The DIGITAL UNIX directory structure does not contain the /usr/etc or /usr/ucb directories. Most commands that reside in these directories on an ULTRIX system are, on the DIGITAL UNIX system, in the /usr/bin directory. This change should not affect you, but you should remove /usr/ucb and /usr/etc from your path definition and add /usr/bin.

Other than these differences, you should notice no difference between the directory structures on the ULTRIX and DIGITAL UNIX systems during daily use.

2.3 Differences in User Applications and Commands

The following list describes the user applications that are packaged on the DIGITAL UNIX system:

Bookreader
The Bookreader program for DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the Bookreader program on ULTRIX workstations. For information about using Bookreader, see dxbook(1X) or start the Bookreader program and read its online help information.

Calculators
The bc and dc calculators are the same on the DIGITAL UNIX system as they are on the ULTRIX system. The DIGITAL UNIX system does not supply the DECwindows Calculator program dxcalc. Use the xcalc program instead; a link from dxcalc to xcalc is provided. For information about using these calculator programs, see bc(1), dc(1), and xcalc(1X).

Calendar
The Calendar program for DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the one on ULTRIX workstations. For information about using the Calendar program, see dxcalendar(1X) or start the Calendar program and read its online help information.

Cardfiler
The Cardfiler program for DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the one on ULTRIX workstations. For information about using the Cardfiler program, see dxcardfiler(1X) or start the Cardfiler program and read its online help information.

CDA Viewer
The CDA Viewer program on DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the one on ULTRIX workstations. For information about using the CDA Viewer, see dxvdoc(1X). You can also start the CDA Viewer and read its online help information.

DECterm
The DECterm terminal emulator program for DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the one on ULTRIX workstations. For information about using DECterm, see dxterm(1X) or start a DECterm window and read the online help information.

Editors and other pattern-scanning tools
The ed, ex, sed, vi, and GNU Emacs editors are the same as the editors of the same names on the ULTRIX system. For information on using these editors, see ed(1), ex(1), sed(1), and vi(1). The GNU Emacs editor features an operational xmenu interface, and is described in the GNU Emacs Manual. If the Emacs editor is installed on your system, this manual is contained in the following PostScript file:
```
/usr/lib/emacs/doc/emacs.ps
```
The DIGITAL UNIX distribution media also includes the Emacs source code as an optional item.
The awk program is essentially the same as the ULTRIX awk program. For information on awk, see awk(1). The sed editor and the awk program are also discussed in Programming Support Tools. The gawk program is essentially the same as the ULTRIX nawk program. For information on gawk, see gawk(1). The DECwindows Notepad program, which is also an editor, is described later in this list.

Examples
The DIGITAL UNIX system includes a full suite of demos and sample programs in the /usr/examples/motif library, including the xcd and periodic programs. The xcd program allows you to play music compact discs in a RRD42 CD-ROM drive attached to your system. The periodic program displays a periodic chart of Motif widgets.

General-purpose commands
Commands for searching files (such as grep), listing directory contents and moving between directories (ls, cd, and pwd), displaying the date and time (date), and so on are, in most cases, the same as the ULTRIX equivalent commands. Differences are noted in Appendix A. The ps command functions in either of the following two ways:
- If you omit the minus sign before the option keywords (for example, ps x), the command functions like the BSD ps command.
- If you include the minus sign (for example, ps -x), the command functions like the System V ps command.
The two versions have different lists of options; see ps(1).

Mail
DIGITAL UNIX mail commands are the same as their ULTRIX equivalents except that the command names are different. The mail command on an ULTRIX system invokes /usr/ucb/mail (the Mail user agent). To use this mail handler on a DIGITAL UNIX system, enter the Mail or the mailx command. The DIGITAL UNIX user interface for the mailx user agent is slightly different from that of the ULTRIX version. The mail command on a DIGITAL UNIX system invokes the /bin/mail program (the binmail user agent). You can use the Message Handler Utility (MH) just as you use MH on an ULTRIX system, with the exception that the DIGITAL UNIX MH utility does not support bulletin boards. For information about using the binmail and mailx commands and the MH utility, see binmail(1), mailx(1), and mh(1).
The DECwindows Mail program on DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the DECwindows Mail program on ULTRIX workstations. For information on other differences and on using DECwindows Mail, see dxmail(1X).

Notepad
The Notepad program on DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the one on ULTRIX workstations. For information about using the Notepad program, see dxnotepad(1X) or start the Notepad program and read its online help information.

Paint
The Paint program on DIGITAL UNIX workstations has a user interface based on Motif, and is similar to the one on ULTRIX workstations.

Reference pages
Reference pages that describe the various DIGITAL UNIX commands are on line. You can read the references pages on line by using the man command, just as on an ULTRIX system. For example, enter the following command at your system prompt:
```
% man man
```
This command displays the man command's reference page.
The section numbers for some reference pages have changed. For example, on ULTRIX systems, Section 4 describes special files. On DIGITAL UNIX systems, Section 4 describes file formats. The following list describes the sections that compose the DIGITAL UNIX reference pages:
- Section 1 describes user commands.
- Section 2 describes system calls.
- Section 3 describes library routines.
- Section 4 describes file formats.
- Section 5 describes macro packages and conventions.
- Section 6 describes games and unsupported programs. As supplied by DIGITAL, this section is empty.
- Section 7 describes special files.
- Section 8 describes system and network administration commands.
Also, the reference pages are stored under the /usr/share/man directory on DIGITAL UNIX systems. On ULTRIX systems, the reference pages are stored in the /usr/man directory.

Remote system commands
The rdate, rlogin, rsh, rwho, and ruptime remote login commands are the same as the ULTRIX equivalent commands. You can use these commands to communicate with remote DIGITAL UNIX systems, ULTRIX systems, and other systems that offer BSD network support. For information about using these commands, see rdate(1), rlogin(1), rsh(1), rwho(1), and ruptime(1).

Remote file transfer commands
The ftp, tftp, and rcp commands are the same as the ULTRIX equivalent commands. You can use these commands to transfer files between DIGITAL UNIX and ULTRIX systems, and between DIGITAL UNIX and other systems that offer Internet networking support. For information about using these commands, see ftp(1), tftp(1), and rcp(1).
The uucp command on DIGITAL UNIX systems differs from the uucp command on ULTRIX systems. The DIGITAL UNIX uucp command has some features that the ULTRIX uucp command does not have. The DIGITAL UNIX uucp command does not support the -W option. For more information about using the DIGITAL UNIX uucp command, see uucp(1).

talk command
The talk command is the same as the ULTRIX talk command. For information about using the talk command, see talk(1).

telnet command
The telnet command is the same as the ULTRIX telnet command. For information about using telnet, see telnet(1).

Text formatting commands
The deroff, neqn, nroff, and tbl commands are similar to the equivalent commands from the VAX ULTRIX system. Some of these commands have different options, and VAX ULTRIX nroff drivers can be ported to a DIGITAL UNIX system. (RISC ULTRIX nroff drivers cannot be ported.) The default device for DIGITAL UNIX nroff is -Tlp; the ULTRIX default is -T37 (Teletype Model 37). For more information about these commands, see deroff(1), neqn(1), nroff(1), and tbl(1).

User information commands
Commands such as finger, w, and who are the same as the ULTRIX equivalent commands. For more information about these commands, see finger(1), w(1), and who(1).

Visual differences program
The dxdiff DECwindows visual differences program is the same as the ULTRIX dxdiff program. For information about dxdiff, see dxdiff(1X).

2.4 Differences in Shells

The DIGITAL UNIX system supports three shells: the C shell (csh), the Korn shell (ksh), and the Bourne shell (sh). This section gives a brief overview of each shell's features and syntax, highlighting differences between it and the equivalent ULTRIX shell.

2.4.1 Differences in the C Shell

The C shell is an interactive command interpreter and a command programming language that uses a syntax similar to the C programming language. The shell carries out commands either from a shell script or interactively from a terminal keyboard.

In most respects, the DIGITAL UNIX C shell is the same as the ULTRIX C shell. In the DIGITAL UNIX C shell, you must set an environment variable to enable file name completion on a DIGITAL UNIX system and an environment variable to enable command-line editing. (For information about enabling file name completion, see Section 3.1.1. For information about enabling command-line editing, see Section 3.1.)

The DIGITAL UNIX C shell does not support the hashstat built-in command for debugging the shell. The hashstat command displays statistics that indicate how effective the internal hash table has been at locating commands.

Other than these differences, the DIGITAL UNIX C shell is the same as the ULTRIX C shell. For information about porting C shell scripts, see Section 3.2.3.

For more information about the DIGITAL UNIX C shell, see csh(1).

2.4.2 Differences in the Korn Shell

The Korn shell is an interactive command interpreter and a command programming language. The shell carries out commands either interactively or from a shell script. The Korn shell contains many of the features of the Bourne shell, as well as some C shell features.

The DIGITAL UNIX Korn shell is the same as the ULTRIX Korn shell. If you use the ULTRIX Korn shell interactively, you should notice no difference when you use the DIGITAL UNIX Korn shell interactively. Shell scripts written for the ULTRIX Korn shell should run without modification using the DIGITAL UNIX Korn shell.

For more information about the DIGITAL UNIX Korn shell, see ksh(1).

2.4.3 Differences in the Bourne Shell

The Bourne shell is an interactive command interpreter and a command programming language. The shell carries out commands either interactively or from a shell script. The Bourne shell is the default system shell on a DIGITAL UNIX system.

The ULTRIX system has two versions of the Bourne shell, sh and sh5. The Bourne shell on the DIGITAL UNIX system is most similar to sh5.

If you use the sh shell on an ULTRIX system, you might notice the following differences when you use sh on a DIGITAL UNIX system:

The shell determines whether the argument you specify to the built-in cd command is a subdirectory of any of the directories specified in the definition of the CDPATH environment variable. If the shell finds a subdirectory that matches the argument you specify, it changes your current directory to that subdirectory. The ULTRIX sh shell does not have this feature.

The default search path for the DIGITAL UNIX sh shell is /usr/bin. On the ULTRIX system, the default search path is :/bin:/usr/bin. On the DIGITAL UNIX system, /bin is a link to /usr/bin; you do not need to add /bin to the definition of your DIGITAL UNIX PATH environment variable.

The Bourne shell on ULTRIX has one variant of the shell command, set - , that does not exist on DIGITAL UNIX systems.

The DIGITAL UNIX Bourne shell contains a built-in echo command. The ULTRIX Bourne shell does not contain an echo command.

These differences might affect the portability of your sh shell scripts. For information about porting sh shell scripts, see Section 3.2.

The DIGITAL UNIX Bourne shell (sh) is almost identical to the ULTRIX sh5 shell; however, its name is different, and there are a few other minor differences. The difference in name does not affect how you use the Bourne shell interactively; however, it might affect the portability of your sh5 shell scripts. Other differences are very minor but can cause subtle failures of ported scripts. For information about porting sh5 shell scripts, see Section 3.2.

2.5 Differences in Security Features

Like the ULTRIX operating system, the DIGITAL UNIX system includes features that allow you to control access to your account, files, and workstation. For information on using the DIGITAL UNIX security features, see the Security manual.

The DIGITAL UNIX system omits the following security features that are found on ULTRIX systems: trusted path, audit, and enhanced identification and authentication features (including the shadow password file). For example, the DIGITAL UNIX system does not support the equivalent of the ULTRIX authenticate_user programming interface. Additionally, a DIGITAL UNIX system's system administrator cannot define a Secure Attention Key that you press before you log in to the system.