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