U

Ubuntu Linux, 39

udf (Univeral Disk Format) file system, 406

UDP (User Datagram Protocol), 248

ufsdump command, backup using, 423–425

ufsrestore command, 425–426

ufsrestore command required options, 426

UID, 315

ulimit command, 413

umask command, 83–84, 351

umount command, 452

umountall command, 452

uname -a command, 388

uname -s command, 388

Unconditional kill signal, 308

UNICS (Uniplexed Information and Computing System), 9

Unify, 768

Uniplex Business Software, 759–761

uniq command, 564–565

uniq -d command, 565

uniq -u command, 565

UNIX

DOS and Windows emulators under, 532–533

first use of the name, 9

future of, 33

importance of, 4–5

multiuser and multitasking, 5

networking, 5

portability, 5

structure of, 5–7

tools and utilities, 4

what it is, 4

and Windows file structure, 60

UNIX Apache. See Apache

UNIX applications, on DOS/Windows machines, 536–540

UNIX commands. See Command line; Commands

UNIX environment, setting up, 526

UNIX environment emulation tools, 537–540

UNIX file system. See File systems; UNIX System

UNIX files, accessing from Windows machine, 533–535

UNIX firewalls, 514–515

UNIX kernel access to DOS, 540

UNIX machines

connecting to locally, 37–39

connecting to remotely, 40

Windows applications and tools on, 531–533, 788

UNIX mail clients

explained, 227

types of, 228

UNIX 98, 17

UNIX 98 Server, 17

UNIX 98 Workstation, 17

UNIX 95, 16

UNIX 03 Product Standard, 18

UNIX philosophy, 8–9

UNIX Programmer’s Manual, 9

UNIX revolution, contributors to, 29–30

UNIX security level, 354

UNIX servers, in Windows networks, 535–536

UNIX standards, 14–18

UNIX System

(see also File systems)

accessing from Mac OS X, 40

accessing from a PC, 40

activity reporting, 392–393

add-on software, 755–790

administrative logins, 373

birth of, 9–13

capitalization in, 56

currently running processes, 393–394

date and time setup, 371–372

default prompt, 43–44

directory structure, 366–367, 410–412

displaying current users, 389

displaying disk space, 391

displaying disk usage, 392

displaying mounted file systems, 390–391

displaying system definition, 389–390

displaying system name, 388

displaying system state, 389

displaying user names, 389

e-mail on, 227–228

entering commands, 44–48

file types, 60–62

graphical environments, 44

housekeeping, 413–415

incorrect login, 43

interacting with Python, 692–693

logging into, 40–44

logging into from PC, 529

logging out of, 52, 95

login name and password, 41–42

maintenance tasks, 386–395

password security, 42

powering up, 369–370

setting system names, 372

setup procedures, 367–386

software installation, 367–369

startup and shutdown, 373–374

storage media and, 401–406

structure, 404

successful login, 42

superuser administration, 370–371

usage checking, 412–413

using dial-up networking, 530

using NetTerm to access, 530–531

using telnet to access, 529–530

vs. Windows NT, 30–33, 522–528

UNIX System editions (Bell Labs), 10

UNIX System V, 10–11

UNIX System V Release 4, 11

UNIX System V Release 3.0, 10

UNIX System IV, 10

UNIX System III, 10

UNIX System timeline, 26–29

UNIX variants, 521

choosing, 34

future of, 33

installing on a PC, 38–39

widely used, 18–26

UNIX web browsers, 291–293

UNIX and Windows (together), 521–544

basic features, 527–528

command line, 523–525

common commands, 524

environment, 526

GUIs, 523

networking machines, 528

sharing files and applications, 533–536

sharing one machine, 540–542

similarities between, 528

terminal emulation, 529–531

UnixWare, 11, 24–25

Unmounting a file system

from floppy disk, 409

from hard disk, 409

unshare all command, 450

unshare command, 449–450

unshift function (Perl), 651

until command, 605

Update Agent (up2date), Red Hat, 368

Upward compatibility, 10

URLs (Uniform Resource Locators), 290, 295–298

abstract look at, 299–300

personal, 298–299

Usenet, 273–285

article distribution, 274–275

background, 273–274

User access, blocking, 381–382

User authentication, NFS, 513

User daemons, explained, 312

User-defined functions, in Python, 687–688

User-defined procedures, in Perl, 656–657

User directories, Apache, 470–471

User environment

changing default, 376

displaying default, 376

User groups

adding, 383

deleting, 383

User IDs, 328–330

User-level security, 250

User login, managing, 376

User names, displaying, 389

User password aging, 381

User passwords, 379–381

User .profile files, 377–378, 526

useradd command, 376–380, 383

useradd command options, 379

userdel command, 382

usermod command, 381, 383

Users

adding, 377–379

classes of, 80

communicating with, 386–388

getting information about, 264–266

hard delete of, 382

security guidelines for, 351–352

soft delete of, 382

USL (UNIX System Labs), 11

Utilities, UNIX, 4–7

UUCP system, 247