All rights reserved.
%sccs.include.redist.roff%
@(#)title.urm 8.13 (Berkeley) 08/08/94
.af % i .nr LL 6.5i .EH '''' .OH '''' .EF '''' .OF '''' \& .nr PS 36 .nr VS 39
2 4.4BSD User's Reference Manual .nr PS 24 .nr VS 32
1 (URM) .bp \& .nr PS 14 .nr VS 16.5
Now in its twentieth year, the USENIX Association, the UNIX and Advanced Computing Systems professional and technical organization, is a not-for-profit membership association of individuals and institutions with an interest in UNIX and UNIX-like systems, and, by extension, C++, X windows, and other advanced tools and technologies.
USENIX and its members are dedicated to:
USENIX publishes a journal (Computing Systems), a newsletter (;login:), Proceedings from its frequent Conferences and Symposia, and a Book Series.
SAGE, The Systems Administrators Guild, a Special Technical Group with the USENIX Association, is dedicated to the advancement of system administration as a profession.
SAGE brings together systems managers and administrators to:
3 4.4BSD User's Reference Manual .nr PS 24 .nr VS 32
1 (URM) .nr PS 24 .nr VS 26
1 Berkeley Software Distribution .nr PS 18 .nr VS 26
1 April, 1994 .nr PS 18 .nr VS 20
2 Computer Systems Research Group University of California at Berkeley .nr PS 12 .nr VS 14.5
4 A USENIX Association Book O'Reilly & Associates, Inc. 103 Morris Street, Suite A Sebastopol, CA 94572 .bp .nr PS 9 .nr VS 11
First Printing, 1994
Second Printing, 1995
Copyright 1979, 1980, 1983, 1986, 1993, 1994 The Regents of the University of California. All rights reserved.
Other than the specific manual pages and documents listed below as copyrighted by AT&T, redistribution and use of this manual in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
\s-1THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\s+1
The Institute of Electrical and Electronics Engineers and the American National Standards Committee X3, on Information Processing Systems have given us permission to reprint portions of their documentation.
In the following statement, the phrase ``this text'' refers to portions of the system documentation.
``Portions of this text are reprinted and reproduced in electronic form in 4.4BSD from IEEE Std 1003.1-1988, IEEE Standard Portable Operating System Interface for Computer Environments (POSIX), copyright 1988 by the Institute of Electrical and Electronics Engineers, Inc. In the event of any discrepancy between these versions and the original IEEE Standard, the original IEEE Standard is the referee document.''
In the following statement, the phrase ``This material'' refers to portions of the system documentation.
``This material is reproduced with permission from American National Standards Committee X3, on Information Processing Systems. Computer and Business Equipment Manufacturers Association (CBEMA), 311 First St., NW, Suite 500, Washington, DC 20001-2178. The developmental work of Programming Language C was completed by the X3J11 Technical Committee.''
Manual pages adb.1, bc.1, compact.1, crypt.1, dc.1, deroff.1, expr.1, graph.1, ld.1, learn.1, m4.1, plot.1, ptx.1, spell.1, spline.1, struct.1, tar.1, units.1, uucp.1, uux.1, ching.6, eqnchar.7, man.7, ms.7, and term.7 are copyright 1979, AT&T Bell Laboratories, Incorporated. Holders of \x'-1p'UNIX\v'-4p'\s-3TM\s0\v'4p'/32V, System III, or System V software licenses are permitted to copy these documents, or any portion of them, as necessary for licensed use of the software, provided this copyright notice and statement of permission are included.
The 4.4BSD Daemon used on the cover is copyright 1994 by Marshall Kirk McKusick and is reproduced with permission.
The views and conclusions contained in this manual are those of the authors and should not be interpreted as representing official policies, either expressed or implied, of the Regents of the University of California.
This book was printed and bound in the United States of America.
Distributed by O'Reilly & Associates, Inc.
ISBN: 1-56592-075-9 .bp \& .nr PS 24 .nr VS 26
1 Contents .nr PS 14 .nr VS 17
| The Computer Systems Research Group, 1979-1993 vii |
| Prefaces xi |
| Introduction xvii |
| List of Manual Pages xxiii |
| Permuted Index xli |
| Reference Manual Sections 1, 6, 7 tabbed pages |
| List of Documents inside back cover |
The contributor list below is derived from the file that resides in
vangogh:~admin/contrib/contrib:
@(#)contrib 5.55 (Berkeley) 4/18/94
This file should not be editted, rather the original contrib file
should be used to recrete this one following the directions at its top.
Contrib starts here and continues to the comment `END OF CONTRIB'.
\& .vs 27
2 The Computer Systems Research Group 1979 - 1993 .nr PS 11 .nr VS 12
CSRG Technical Staff Jim Bloom Keith Bostic Ralph Campbell Kevin Dunlap William N. Joy Michael J. Karels Samuel J. Leffler Marshall Kirk McKusick Miriam Amos Nihart Keith Sklower Marc Teitelbaum Michael Toy CSRG Administration and Support Robert Fabry Domenico Ferrari Susan L. Graham Bob Henry Anne Hughes Bob Kridle David Mosher Pauline Schwartz Mark Seiden Jean WoodOrganizations that funded the CSRG with grants, gifts, personnel, and/or hardware.
Center for Advanced Aviation System Development, The MITRE Corp. Compaq Computer Corporation Cray Research Inc. Department of Defense Advance Research Projects Agency (DARPA) Digital Equipment Corporation The Hewlett-Packard Company NASA Ames Research Center The National Science Foundation The Open Software Foundation UUNET Technologies Inc..OH '\s10CSRG, 1979 - 1993''- % -\s0' .EH '\s10- % -''CSRG, 1979 - 1993\s0' .bp .nr PS 10 .nr VS 11
The following are people and organizations that provided a large subsystem for the BSD releases.
| ANSI C library Chris Torek |
| ANSI C prototypes Donn Seeley and John Kohl |
| Autoconfiguration Robert Elz |
| C library documentation American National Standards Committee X3 |
| CCI 6/32 support Computer Consoles Inc. |
| DEC 3000/5000 support Ralph Campbell |
| Disklabels Symmetric Computer Systems |
| Documentation Cynthia Livingston and The USENIX Association |
| Franz Lisp Richard Fateman, John Foderaro, Keith Sklower, Kevin Layer |
| GCC, GDB The Free Software Foundation |
| Groff James Clark (The FSF) |
| HP300 support Jeff Forys, Mike Hibler, Jay Lepreau, Donn Seeley and the Systems |
| Programming Group; University of Utah Computer Science Department |
| ISODE Marshall Rose |
| Ingres Mike Stonebraker, Gene Wong, and the Berkeley Ingres Research Group |
| Intel 386/486 support Bill Jolitz and TeleMuse |
| Job control Jim Kulp |
| Kerberos Project Athena and MIT |
| Kernel support Bill Shannon and Sun Microsystems Inc. |
| LFS Margo Seltzer, Mendel Rosenblum, Carl Staelin |
| MIPS support Trent Hein |
| Math library K.C. Ng, Zhishun Alex Liu, S. McDonald, P. Tang and W. Kahan |
| NFS Rick Macklem |
| NFS automounter Jan-Simon Pendry |
| Network device drivers Micom-Interlan and Excelan |
| Omron Luna support Akito Fujita and Shigeto Mochida |
| Quotas Robert Elz |
| RPC support Sun Microsystems Inc. |
| Shared library support Rob Gingell and Sun Microsystems Inc. |
| Sony News 3400 support Kazumasa Utashiro |
| Sparc I/II support Computer Systems Engineering Group, Lawrence Berkeley Laboratory |
| Stackable file systems John Heidemann |
| Stdio Chris Torek |
| System documentation The Institute of Electrical and Electronics Engineers, Inc. |
| TCP/IP Rob Gurwitz and Bolt Beranek and Newman Inc. |
| Timezone support Arthur David Olson |
| Transport/Network OSI layers IBM Corporation and the University of Wisconsin |
| Kernel XNS assistance William Nesheim, J. Q. Johnson, Chris Torek, and James O'Toole |
| User level XNS Cornell University |
| VAX 3000 support Mt. Xinu and Tom Ferrin |
| VAX BI support Chris Torek |
| VAX device support Digital Equipment Corporation and Helge Skrivervik |
| Versatec printer/plotter support University of Toronto |
| Virtual memory implementation Avadis Tevanian, Jr., Michael Wayne Young, |
| and the Carnegie-Mellon University Mach project |
| X25 University of British Columbia |
The following are people and organizations that provided a specific item, program, library routine or program maintenance for the BSD system. (Their contribution may not be part of the final 4.4BSD release.) .nr PS 9 .nr VS 10 .vs 10
| 386 device drivers Carnegie-Mellon University Mach project |
| 386 device drivers Don Ahn, Sean Fagan and Tim Tucker |
| HCX device drivers Harris Corporation |
| Kernel enhancements Robert Elz, Peter Ivanov, Ian Johnstone, Piers Lauder, |
| John Lions, Tim Long, Chris Maltby, Greg Rose and John Wainwright |
| ISO-9660 filesystem Pace Willisson, Atsushi Murai |
| adventure(6) Don Woods log(3) Peter McIlroy |
| adventure(6) Jim Gillogly look(1) David Hitz |
| adventure(6) Will Crowther ls(1) Elan Amir |
| apply(1) Rob Pike ls(1) Michael Fischbein |
| apply(1) Jan-Simon Pendry lsearch(3) Roger L. Snyder |
| ar(1) Hugh A. Smith m4(1) Ozan Yigit |
| arithmetic(6) Eamonn McManus mail(1) Kurt Schoens |
| arp(8) Sun Microsystems Inc. make(1) Adam de Boor |
| at(1) Steve Wall me(7) Eric Allman |
| atc(6) Ed James mergesort(3) Peter McIlroy |
| awk(1) Arnold Robbins mh(1) Marshall Rose |
| awk(1) David Trueman mh(1) The Rand Corporation |
| backgammon(6) Alan Char mille(6) Ken Arnold |
| banner(1) Mark Horton mknod(8) Kevin Fall |
| battlestar(6) David Riggle monop(6) Ken Arnold |
| bcd(6) Steve Hayman more(1) Eric Shienbrood |
| bdes(1) Matt Bishop more(1) Mark Nudleman |
| berknet(1) Eric Schmidt mountd(8) Herb Hasler |
| bib(1) Dain Samples mprof(1) Ben Zorn |
| bib(1) Gary M. Levin msgs(1) David Wasley |
| bib(1) Timothy A. Budd multicast Stephen Deering |
| bitstring(3) Paul Vixie mv(1) Ken Smith |
| boggle(6) Barry Brachman named/bind(8) Douglas Terry |
| bpf(4) Steven McCanne named/bind(8) Kevin Dunlap |
| btree(3) Mike Olson news(1) Rick Adams (and a cast of thousands) |
| byte-range locking Scooter Morris nm(1) Hans Huebner |
| caesar(6) John Eldridge pascal(1) Kirk McKusick |
| caesar(6) Stan King pascal(1) Peter Kessler |
| cal(1) Kim Letkeman paste(1) Adam S. Moskowitz |
| cat(1) Kevin Fall patch(1) Larry Wall |
| chess(6) Stuart Cracraft (The FSF) pax(1) Keith Muller |
| ching(6) Guy Harris phantasia(6) C. Robertson |
| cksum(1) James W. Williams phantasia(6) Edward A. Estes |
| clri(8) Rich $alz ping(8) Mike Muuss |
| col(1) Michael Rendell pom(6) Keith E. Brandt |
| comm(1) Case Larsen pr(1) Keith Muller |
| compact(1) Colin L. McMaster primes(6) Landon Curt Noll |
| compress(1) James A. Woods qsort(3) Doug McIlroy |
| compress(1) Joseph Orost qsort(3) Earl Cohen |
| compress(1) Spencer Thomas qsort(3) Jon Bentley |
| courier(1) Eric Cooper quad(3) Chris Torek |
| cp(1) David Hitz quiz(6) Jim R. Oldroyd |
| cpio(1) AT&T quiz(6) Keith Gabryelski |
| crypt(3) Tom Truscott radixsort(3) Dan Bernstein |
| csh(1) Christos Zoulas radixsort(3) Peter McIlroy |
| csh(1) Len Shar rain(6) Eric P. Scott |
| curses(3) Elan Amir ranlib(1) Hugh A. Smith |
| curses(3) Ken Arnold rcs(1) Walter F. Tichy |
| cut(1) Adam S. Moskowitz rdist(1) Michael Cooper |
| cut(1) Marciano Pitargue regex(3) Henry Spencer |
| dbx(1) Mark Linton robots(6) Ken Arnold |
| dd(1) Keith Muller rogue(6) Timothy C. Stoehr |
| dd(1) Lance Visser rs(1) John Kunze |
| des(1) Jim Gillogly sail(6) David Riggle |
| des(1) Phil Karn sail(6) Edward Wang |
| des(1) Richard Outerbridge sccs(1) Eric Allman |
| dipress(1) Xerox Corporation scsiformat(1) Lawrence Berkeley Laboratory |
| disklabel(8) Symmetric Computer Systems sdb(1) Howard Katseff |
| du(1) Chris Newcomb sed(1) Diomidis Spinellis |
| dungeon(6) R.M. Supnik sendmail(8) Eric Allman |
| ed(1) Rodney Ruddock setmode(3) Dave Borman |
| emacs(1) Richard Stallman sh(1) Kenneth Almquist |
| erf(3) Peter McIlroy, K.C. Ng slattach(8) Rick Adams |
| error(1) Robert R. Henry slip(8) Rick Adams |
| ex(1) Mark Horton spms(1) Peter J. Nicklin |
| factor(6) Landon Curt Noll strtod(3) David M. Gay |
| file(1) Ian Darwin swab(3) Jeffrey Mogul |
| find(1) Cimarron Taylor sysconf(3) Sean Eric Fagan |
| finger(1) Tony Nardo sysline(1) J.K. Foderaro |
| fish(6) Muffy Barkocy syslog(3) Eric Allman |
| fmt(1) Kurt Schoens systat(1) Bill Reeves |
| fnmatch(3) Guido van Rossum systat(1) Robert Elz |
| fold(1) Kevin Ruddy tail(1) Edward Sze-Tyan Wang |
| fortune(6) Ken Arnold talk(1) Clem Cole |
| fpr(1) Robert Corbett talk(1) Kipp Hickman |
| fsdb(8) Computer Consoles Inc. talk(1) Peter Moore |
| fsplit(1) Asa Romberger telnet(1) Dave Borman |
| fsplit(1) Jerry Berkman telnet(1) Paul Borman |
| gcc/groff integration UUNET Technologies, Inc. termcap(5) John A. Kunze |
| gcore(1) Eric Cooper termcap(5) Mark Horton |
| getcap(3) Casey Leedom test(1) Kenneth Almquist |
| glob(3) Guido van Rossum tetris(6) Chris Torek |
| gprof(1) Peter Kessler tetris(6) Darren F. Provine |
| gprof(1) Robert R. Henry timed(8) Riccardo Gusella |
| hack(6) Andries Brouwer (and a cast of thousands) timed(8) Stefano Zatti |
| hangman(6) Ken Arnold tn3270(1) Gregory Minshall |
| hash(3) Margo Seltzer tr(1) Igor Belchinskiy |
| heapsort(3) Elmer Yglesias traceroute(8) Van Jacobson |
| heapsort(3) Kevin Lew trek(6) Eric Allman |
| heapsort(3) Ronnie Kon tset(1) Eric Allman |
| hunt(6) Conrad Huang tsort(1) Michael Rendell |
| hunt(6) Greg Couch unifdef(1) Dave Yost |
| icon(1) Bill Mitchell uniq(1) Case Larsen |
| icon(1) Ralph Griswold uucpd(8) Rick Adams |
| indent(1) David Willcox uudecode(1) Mark Horton |
| indent(1) Eric Schmidt uuencode(1) Mark Horton |
| indent(1) James Gosling uuq(1) Lou Salkind |
| indent(1) Sun Microsystems uuq(1) Rick Adams |
| init(1) Donn Seeley uusnap(8) Randy King |
| j0(3) Sun Microsystems, Inc. uusnap(8) Rick Adams |
| j1(3) Sun Microsystems, Inc. vacation(1) Eric Allman |
| jn(3) Sun Microsystems, Inc. vi(1) Steve Kirkendall |
| join(1) David Goodenough which(1) Peter Kessler |
| join(1) Michiro Hikida who(1) Michael Fischbein |
| join(1) Steve Hayman window(1) Edward Wang |
| jot(1) John Kunze worm(6) Michael Toy |
| jove(1) Jonathon Payne worms(6) Eric P. Scott |
| kermit(1) Columbia University write(1) Craig Leres |
| kvm(3) Peter Shipley write(1) Jef Poskanzer |
| kvm(3) Steven McCanne wump(6) Dave Taylor |
| lam(1) John Kunze X25/Ethernet Univ. of Erlangen-Nuremberg |
| larn(6) Noah Morgan X25/LLC2 Dirk Husemann |
| lastcomm(1) Len Edmondson xargs(1) John B. Roll Jr. |
| lex(1) Vern Paxson xneko(6) Masayuki Koba |
| libm(3) Peter McIlroy XNSrouted(1) Bill Nesheim |
| libm(3) UUNET Technologies, Inc. xroach(6) J.T. Anderson |
| locate(1) James A. Woods yacc(1) Robert Paul Corbett |
| lock(1) Bob Toxen |
END OF CONTRIB: Contrib ends here.
\& .EH '''' .OH '''' .bp .OH '\s10Preface''- % -\s0' .EH '\s10- % -''Preface\s0' .nr PS 10 .nr VS 12 \& delim $$ .EN
\s24Preface\s0 Introduction
The major new facilities available in the 4.4BSD release are a new virtual memory system, the addition of ISO/OSI networking support, a new virtual filesystem interface supporting filesystem stacking, a freely redistributable implementation of NFS, a log-structured filesystem, enhancement of the local filesystems to support files and filesystems that are up to $2 sup 63$ bytes in size, enhanced security and system management support, and the conversion to and addition of the IEEE Std1003.1 (``POSIX'') facilities and many of the IEEE Std1003.2 facilities. In addition, many new utilities and additions have been made to the C-library. The kernel sources have been reorganized to collect all machine-dependent files for each architecture under one directory, and most of the machine-independent code is now free of code conditional on specific machines. The user structure and process structure have been reorganized to eliminate the statically-mapped user structure and to make most of the process resources shareable by multiple processes. The system and include files have been converted to be compatible with ANSI C, including function prototypes for most of the exported functions. There are numerous other changes throughout the system. Changes in the Kernel
This release includes several important structural kernel changes. The kernel uses a new internal system call convention; the use of global (``u-dot'') variables for parameters and error returns has been eliminated, and interrupted system calls no longer abort using non-local goto's (longjmp's). A new sleep interface separates signal handling from scheduling priority, returning characteristic errors to abort or restart the current system call. This sleep call also passes a string describing the process state, which is used by the ps(1) program. The old sleep interface can be used only for non-interruptible sleeps.
Many data structures that were previously statically allocated are now allocated dynamically. These structures include mount entries, file entries, user open file descriptors, the process entries, the vnode table, the name cache, and the quota structures.
The 4.4BSD distribution adds support for several new architectures including SPARC-based Sparcstations 1 and 2, MIPS-based Decstation 3100 and 5000 and Sony NEWS, 68000-based Hewlett-Packard 9000/300 and Omron Luna, and 386-based Personal Computers. Both the HP300 and SPARC ports feature the ability to run binaries built for the native operating system (HP-UX or SunOS) by emulating their system calls. Though this native operating system compatibility was provided by the developers as needed for their purposes and is by no means complete, it is complete enough to run several non-trivial applications including those that require HP-UX or SunOS shared libraries. For example, the vendor supplied X11 server and windowing environment can be used on both the HP300 and SPARC. Virtual memory changes
The new virtual memory implementation is derived from the MACH operating system developed at Carnegie-Mellon, and was ported to the BSD kernel at the University of Utah. The MACH virtual memory system call interface has been replaced with the ``mmap''-based interface described in the ``Berkeley Software Architecture Manual (4.4 Edition)'' (see the UNIX Programmer's Manual, Supplementary Documents, PSD:5). The interface is similar to the interfaces shipped by several commercial vendors such as Sun, USL, and Convex Computer Corp. The integration of the new virtual memory is functionally complete, but, like most MACH-based virtual memory systems, still has serious performance problems under heavy memory load. Networking additions and changes
The ISO/OSI Networking consists of a kernel implementation of
transport class 4 (TP-4),
connectionless networking protocol (CLNP),
and 802.3-based link-level support (hardware-compatible with Ethernet*).
ditroff screws up the environment for footnote. This restores it.
.ev 1
.vs 9
.ev
end of ditroff fix
.FS
*Ethernet is a trademark of the Xerox Corporation.
.FE
We also include support for ISO Connection-Oriented Network Service,
X.25, and TP-0.
The session and presentation layers are provided outside
the kernel by the ISO development environment (ISODE).
Included in this development environment are file
transfer and management (FTAM), virtual terminals (VT),
a directory services implementation (X.500), and miscellaneous other utilities.
Several important enhancements have been added to the TCP/IP protocols including TCP header prediction and serial line IP (SLIP) with header compression. The routing implementation has been completely rewritten to use a hierarchical routing tree with a mask per route to support the arbitrary levels of routing found in the ISO protocols. The routing table also stores and caches route characteristics to speed the adaptation of the throughput and congestion avoidance algorithms. Additions and changes to filesystems
The 4.4BSD distribution contains most of the interfaces specified in the IEEE Std1003.1 system interface standard. Filesystem additions include IEEE Std1003.1 FIFOs, byte-range file locking, and saved user and group identifiers.
A new virtual filesystem interface has been added to the kernel to support multiple filesystems. In comparison with other interfaces, the Berkeley interface has been structured for more efficient support of filesystems that maintain state (such as the local filesystem). The interface has been extended with support for stackable filesystems done at UCLA. These extensions allow for filesystems to be layered on top of each other and allow new vnode operations to be added without requiring changes to existing filesystem implementations. For example, the umap filesystem is used to mount a sub-tree of an existing filesystem that uses a different set of uids and gids than the local system. Such a filesystem could be mounted from a remote site via NFS or it could be a filesystem on removable media brought from some foreign location that uses a different password file.
In addition to the local ``fast filesystem,'' we have added an implementation of the network filesystem (NFS) that fully interoperates with the NFS shipped by Sun and its licensees. Because our NFS implementation was implemented using only the publicly available NFS specification, it does not require a license from Sun to use in source or binary form. By default it runs over UDP to be compatible with Sun's implementation. However, it can be configured on a per-mount basis to run over TCP. Using TCP allows it to be used quickly and efficiently through gateways and over long-haul networks. Using an extended protocol, it supports Leases to allow a limited callback mechanism that greatly reduces the network traffic necessary to maintain cache consistency between the server and its clients.
A new log-structured filesystem has been added that provides near disk-speed output and fast crash recovery. It is still experimental in the 4.4BSD release, so we do not recommend it for production use. We have also added a memory-based filesystem that runs in pageable memory, allowing large temporary filesystems without requiring dedicated physical memory.
The local ``fast filesystem'' has been enhanced to do clustering which allows large pieces of files to be allocated contiguously resulting in near doubling of filesystem throughput. The filesystem interface has been extended to allow files and filesystems to grow to $2 sup 63$ bytes in size. The quota system has been rewritten to support both user and group quotas (simultaneously if desired). Quota expiration is based on time rather than the previous metric of number of logins over quota. This change makes quotas more useful on fileservers onto which users seldom log in.
The system security has been greatly enhanced by the addition of additional file flags that permit a file to be marked as immutable or append only. Once set, these flags can only be cleared by the super-user when the system is running single user. To protect against indiscriminate reading or writing of kernel memory, all writing and most reading of kernel data structures must be done using a new ``sysctl'' interface. The information to be accessed is described through an extensible ``Management Information Base'' (MIB). delim off .EN POSIX terminal driver changes
The biggest area of change is a new terminal driver. The terminal driver is similar to the System V terminal driver with the addition of the necessary extensions to get the functionality previously available in the 4.3BSD terminal driver. 4.4BSD also adds the IEEE Std1003.1 job control interface, which is similar to the 4.3BSD job control interface, but adds a security model that was missing in the 4.3BSD job control implementation. A new system call, setsid, creates a job-control session consisting of a single process group with one member, the caller, that becomes a session leader. Only a session leader may acquire a controlling terminal. This is done explicitly via a \s-1TIOCSCTTY\s+1 ioctl call, not implicitly by an open call. The call fails if the terminal is in use.
For backward compatibility, both the old ioctl calls and old options to stty are emulated. Changes to the utilities
There are several new tools and utilities included in this release. A new version of ``make'' allows much-simplified makefiles for the system software and allows compilation for multiple architectures from the same source tree (which may be mounted read-only). Notable additions to the libraries include functions to traverse a filesystem hierarchy, database interfaces to btree and hashing functions, a new, fast implementation of stdio, and a radix sort function. The additions to the utility suite include greatly enhanced versions of programs that display system status information, implementations of various traditional tools described in the IEEE Std1003.2 standard, and many others.
We have been tracking the IEEE Std1003.2 shell and utility work and have included prototypes of many of the proposed utilities. Most of the traditional utilities have been replaced with implementations conformant to the POSIX standards. Almost the entire manual suite has been rewritten to reflect the POSIX defined interfaces. In rewriting this software, we have generally been rewarded with significant performance improvements. Most of the libraries and header files have been converted to be compliant with ANSI C. The system libraries and utilities all compile with either ANSI or traditional C.
The Kerberos (version 4) authentication software has been integrated into much of the system (including NFS) to provide the first real network authentication on BSD.
A new implementation of the ex/vi text editors is available in this release. It is intended as a bug-for-bug compatible version of the editors. It also has a few new features: 8-bit clean data, lines and files limited only by memory and disk space, split screens, tags stacks and left-right scrolling among them. Nex/nvi is not yet production quality; future versions of this software may be retrieved by anonymous ftp from ftp.cs.berkeley.edu, in the directory ucb/4bsd.
The find utility has two new options that are important to be aware of if you intend to use NFS. The ``fstype'' and ``prune'' options can be used together to prevent find from crossing NFS mount points. Additions and changes to the libraries
The curses library has been largely rewritten. Important additional features include support for scrolling and termios.
An application front-end editing library, named libedit, has been added to the system.
A superset implementation of the SunOS kernel memory interface library, libkvm, has been integrated into the system.
Nearly the entire C-library has been rewritten. Some highlights of the changes to the 4.4BSD C-library:
We were greatly assisted by the past employees of the Computer Systems Research Group: Mike Karels, Keith Sklower, and Marc Tietelbaum. Our distribution coordinator, Pauline Schwartz, has reliably managed the finances and the mechanics of shipping distributions for nearly the entire fourteen years of the group's existence. Without the help of lawyers Mary MacDonald, Joel Linzner, and Carla Shapiro, the 4.4BSD-Lite distribution would never have seen the light of day. Much help was provided by Chris Demetriou in getting bug fixes from NetBSD integrated back into the 4.4BSD-Lite distribution.
The vast majority of the 4.4BSD distribution comes from the numerous people in the UNIX community that provided their time and energy in creating the software contained in this release. We dedicate this distribution to them.
M. K. McKusick K. Bostic.nr PS 9 .nr VS 10
Preface to the 4.3 Berkeley distribution
This update to the 4.2 distribution of August 1983 provides substantially improved performance, reliability, and security, the addition of Xerox Network System (NS) to the set of networking domains, and partial support for the VAX 8600 and MICROVAXII.
We were greatly assisted by the DEC UNIX Engineering group who provided two full time employees, Miriam Amos and Kevin Dunlap, to work at Berkeley. They were responsible for developing and debugging the distributed domain based name server and integrating it into the mail system. Mt Xinu provided the bug list distribution service as well as donating their MICROVAXII port to 4.3BSD. Drivers for the MICROVAXII were done by Rick Macklem at the University of Guelph. Sam Leffler provided valuable assistance and advice with many projects. Keith Sklower coordinated with William Nesheim and J. Q. Johnson at Cornell, and Chris Torek and James O'Toole at the University of Maryland to do the Xerox Network Systems implementation. Robert Elz at the University of Melbourne contributed greatly to the performance work in the kernel. Donn Seeley and Jay Lepreau at the University of Utah relentlessly dealt with a myriad of details; Donn completed the unfinished performance work on Fortran 77 and fixed numerous C compiler bugs. Ralph Campbell handled innumerable questions and problem reports and had time left to write rdist. George Goble was invaluable in shaking out the bugs on his production systems long before we were confident enough to inflict it on our users. Bill Shannon at Sun Microsystems has been helpful in providing us with bug fixes and improvements. Tom Ferrin, in his capacity as Board Member of Usenix Association, handled the logistics of large-scale reproduction of the 4.2BSD and 4.3BSD manuals. Mark Seiden helped with the typesetting and indexing of the 4.3BSD manuals. Special mention goes to Bob Henry for keeping ucbvax running in spite of new and improved software and an ever increasing mail, news, and uucp load.
Numerous others contributed their time and energy in creating the user contributed software for the release. As always, we are grateful to the UNIX user community for encouragement and support.
Once again, the financial support of the Defense Advanced Research Projects Agency is gratefully acknowledged.
M. K. McKusick M. J. Karels J. M. Bloom
Preface to the 4.2 Berkeley distribution This update to the 4.1 distribution of June 1981 provides support for the VAX 11/730, full networking and interprocess communication support, an entirely new file system, and many other new features. It is certainly the most ambitious release of software ever prepared here and represents many man-years of work. Bill Shannon (both at DEC and at Sun Microsystems) and Robert Elz of the University of Melbourne contributed greatly to this distribution through new device drivers and painful debugging episodes. Rob Gurwitz of BBN wrote the initial version of the code upon which the current networking support is based. Eric Allman of Britton-Lee donated countless hours to the mail system. Bill Croft (both at SRI and Sun Microsystems) aided in the debugging and development of the networking facilities. Dennis Ritchie of Bell Laboratories also contributed greatly to this distribution, providing valuable advise and guidance. Helge Skrivervik worked on the device drivers which enabled the distribution to be delivered with a TU58 console cassette and RX01 console floppy disk, and rewrote major portions of the standalone i/o system to support formatting of non-DEC peripherals.
Numerous others contributed their time and energy in organizing the user software for release, while many groups of people on campus suffered patiently through the low spots of development. As always, we are grateful to the UNIX user community for encouragement and support.
Once again, the financial support of the Defense Advanced Research Projects Agency is gratefully acknowledged.
S. J. Leffler W. N. Joy M. K. McKusick
Preface to the 4.1 Berkeley distribution This update to the fourth distribution of November 1980 provides support for the VAX 11/750 and for the full interconnect architecture of the VAX 11/780. Robert Elz of the University of Melbourne contributed greatly to this distribution especially in the boot-time system configuration code; Bill Shannon of DEC supplied us with the implementation of DEC standard bad block handling. The research group at Bell Laboratories and DEC Merrimack provided us with access to 11/750's in order to debug its support.
Other individuals too numerous to mention provided us with bug reports, fixes and other enhancements which are reflected in the system. We are grateful to the UNIX user community for encouragement and support.
The financial support of the Defense Advanced Research Projects Agency in support of this work is gratefully acknowledged.
W. N. Joy R. S. Fabry K. Sklower
Preface to the Fourth Berkeley distribution This manual reflects the Berkeley system mid-October, 1980. A large amount of tuning has been done in the system since the last release; we hope this provides as noticeable an improvement for you as it did for us. This release finds the system in transition; a number of facilities have been added in experimental versions (job control, resource limits) and the implementation of others is imminent (shared-segments, higher performance from the file system, etc.). Applications which use facilities that are in transition should be aware that some of the system calls and library routines will change in the near future. We have tried to be conscientious and make it very clear where this is likely.
A new group has been formed at Berkeley, to assume responsibility for the future development and support of a version of UNIX on the VAX. The group has received funding from the Defense Advanced Research Projects Agency (DARPA) to supply a standard version of the system to DARPA contractors. The same version of the system will be made available to other licensees of UNIX on the VAX for a duplication charge. We gratefully acknowledge the support of this contract.
We wish to acknowledge the contribution of a number of individuals to the the system.
We would especially like to thank Jim Kulp of IIASA, Laxenburg Austria and his colleagues, who first put job control facilities into UNIX; Eric Allman, Robert Henry, Peter Kessler and Kirk McKusick, who contributed major new pieces of software; Mark Horton, who contributed to the improvement of facilities and substantially improved the quality of our bit-mapped fonts, our hardware support staff: Bob Kridle, Anita Hirsch, Len Edmondson and Fred Archibald, who helped us to debug a number of new peripherals; Ken Arnold who did much of the leg-work in getting this version of the manual prepared, and did the final editing of sections 2-6, some special individuals within Bell Laboratories: Greg Chesson, Stuart Feldman, Dick Haight, Howard Katseff, Brian Kernighan, Tom London, John Reiser, Dennis Ritchie, Ken Thompson, and Peter Weinberger who helped out by answering questions; our excellent local DEC field service people, Kevin Althaus and Frank Chargois who kept our machine running virtually all the time, and fixed it quickly when things broke; and, Mike Accetta of Carnegie-Mellon University, Robert Elz of the University of Melbourne, George Goble of Purdue University, and David Kashtan of the Stanford Research Institute for their technical advice and support.
Special thanks to Bill Munson of DEC who helped by augmenting our computing facility and to Eric Allman for carefully proofreading the ``last'' draft of the manual and finding the bugs which we knew were there but couldn't see.
We dedicate this to the memory of David Sakrison, late chairman of our department, who gave his support to the establishment of our VAX computing facility, and to our department as a whole.
W. N. Joy O\h'-.54m'\v'-.24m'\z\(..\v'.24m'\h'.54m'. Babao\o'~g'lu R. S. Fabry K. Sklower
Preface to the Third Berkeley distribution This manual reflects the state of the Berkeley system, December 1979. We would like to thank all the people at Berkeley who have contributed to the system, and particularly thank Prof. Richard Fateman for creating and administrating a hospitable environment, Mark Horton who helped prepare this manual, and Eric Allman, Bob Kridle, Juan Porcar and Richard Tuck for their contributions to the kernel.
The cooperation of Bell Laboratories in providing us with an early version of \s-2UNIX\s0/32V is greatly appreciated. We would especially like to thank Dr. Charles Roberts of Bell Laboratories for helping us obtain this release, and acknowledge T. B. London, J. F. Reiser, K. Thompson, D. M. Ritchie, G. Chesson and H. P. Katseff for their advice and support. W. N. Joy
O\h'-.54m'\v'-.24m'\z\(..\v'.24m'\h'.54m'. Babao\o'~g'lu
Preface to the UNIX/32V distribution The UNIX operating system for the VAX*-11 .FS *VAX and PDP are Trademarks of Digital Equipment Corporation. .FE provides substantially the same facilities as the \s-2UNIX\s0 system for the PDP*-11.
We acknowledge the work of many who came before us, and particularly thank G. K. Swanson, W. M. Cardoza, D. K. Sharma, and J. F. Jarvis for assistance with the implementation for the VAX-11/780. T. B. London
J. F. Reiser
Preface to the Seventh Edition
Although this Seventh Edition no longer bears their byline, Ken Thompson and Dennis Ritchie remain the fathers and preceptors of the \s-2UNIX\s0 time-sharing system. Many of the improvements here described bear their mark. Among many, many other people who have contributed to the further flowering of \s-2UNIX\s0, we wish especially to acknowledge the contributions of A. V. Aho, S. R. Bourne, L. L. Cherry, G. L. Chesson, S. I. Feldman, C. B. Haley, R. C. Haight, S. C. Johnson, M. E. Lesk, T. L. Lyon, L. E. McMahon, R. Morris, R. Muha, D. A. Nowitz, L. Wehr, and P. J. Weinberger. We appreciate also the effective advice and criticism of T. A. Dolotta, A. G. Fraser, J. F. Maranzano, and J. R. Mashey; and we remember the important work of the late Joseph F. Ossanna. B. W. Kernighan
M. D. McIlroy \& .EH '''' .OH '''' .bp .OH '\s10Introduction''- % -\s0' .EH '\s10- % -''Introduction\s0' \\$1\^\\$2 .. \\$1\\$2\^\\$3 ..
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The documentation for 4.4BSD is in a format similar to the one used for the 4.2BSD and 4.3BSD manuals. It is divided into three sets; each set consists of one or more volumes. The abbreviations for the volume names are listed in square brackets; the abbreviations for the manual sections are listed in parenthesis. I. User's Documents User's Reference Manual [URM] Commands (1) Games (6) Macro packages and language conventions (7) User's Supplementary Documents [USD] Getting Started Basic Utilities Communicating with the World Text Editing Document Preparation Amusements II. Programmer's Documents Programmer's Reference Manual [PRM] System calls (2) Subroutines (3) Special files (4) File formats and conventions (5) Programmer's Supplementary Documents [PSD] Documents of Historic Interest Languages in common use Programming Tools Programming Libraries General Reference III. System Manager's Manual [SMM] Maintenance commands (8) System Installation and Administration
References to individual documents are given as ``volume:document'', thus USD:1 refers to the first document in the ``User's Supplementary Documents''. References to manual pages are given as ``name(section)'' thus sh (1) refers to the shell manual entry in section 1.
The manual pages give descriptions of the features of the 4.4BSD system, as developed at the University of California at Berkeley. They do not attempt to provide perspective or tutorial information about the 4.4BSD operating system, its facilities, or its implementation. Various documents on those topics are contained in the ``\s-1UNIX\s+1 User's Supplementary Documents'' (USD), the ``\s-1UNIX\s+1 Programmer's Supplementary Documents'' (PSD), and ``\s-1UNIX\s+1 System Manager's Manual'' (SMM). In particular, for an overview see ``The \s-1UNIX\s+1 Time-Sharing System'' (PSD:1) by Ritchie and Thompson; for a tutorial see ``\s8\s-1UNIX\s+1\s10 for Beginners'' (USD:1) by Kernighan, and for an guide to the new features of this latest version, see ``Berkeley Software Architecture Manual (4.4 Edition)'' (PSD:5).
Within the area it surveys, this volume attempts to be timely, complete and concise. Where the latter two objectives conflict, the obvious is often left unsaid in favor of brevity. It is intended that each program be described as it is, not as it should be. Inevitably, this means that various sections will soon be out of date.
Commands are programs intended to be invoked directly by the user, in contrast to subroutines, that are intended to be called by the user's programs. User commands are described in URM section 1. Commands generally reside in directory /bin (for bin \|ary programs). Some programs also reside in /\|usr/\|bin, .R to save space in /\|bin. .R These directories are searched automatically by the command interpreters. Additional directories that may be of interest include /\|usr/\|contrib/\|bin, .R which has contributed software /\|usr/\|old/\|bin, .R which has old but sometimes still useful software and /\|usr/\|local/\|bin, .R which contains software local to your site.
Games have been relegated to URM section 6 and /\|usr/\|games, .R to keep them from contaminating the more staid information of URM section 1.
Miscellaneous collection of information necessary for writing in various specialized languages such as character codes, macro packages for typesetting, etc is contained in URM section 7.
System calls are entries into the BSD kernel. The system call interface is identical to a C language procedure call; the equivalent C procedures are described in PRM section 2.
An assortment of subroutines is available; they are described in PRM section 3. The primary libraries in which they are kept are described in intro (3). The functions are described in terms of C.
PRM section 4 discusses the characteristics of each system ``file'' that refers to an I/O device. The names in this section refer to the HP300 device names for the hardware, instead of the names of the special files themselves.
The file formats and conventions (PRM section 5) documents the structure of particular kinds of files; for example, the form of the output of the loader and assembler is given. Excluded are files used by only one command, for example the assembler's intermediate files.
Commands and procedures intended for use primarily by the system administrator are described in SMM section 8. The files described here are almost all kept in the directory /\|etc. The system administration binaries reside in /\|sbin, .R and /\|usr/\|sbin.
Each section consists of independent entries of a page or so each. The name of the entry is in the upper corners of its pages, together with the section number. Entries within each section are alphabetized. The page numbers of each entry start at 1; it is infeasible to number consecutively the pages of a document like this that is republished in many variant forms.
All entries are based on a common format; not all subsections always appear.
The name subsection lists the exact names of the commands and subroutines covered under the entry and gives a short description of their purpose.
The synopsis "" summarizes the use of the program being described. A few conventions are used, particularly in the Commands subsection:
Boldface words are considered literals, and are typed just as they appear.
Square brackets [ ] around an argument show that the argument is optional. When an argument is given as ``name'', it always refers to a file name.
Ellipses ``.\|.\|.'' are used to show that the previous argument-prototype may be repeated.
A final convention is used by the commands themselves. An argument beginning with a minus sign ``-'' usually means that it is an option-specifying argument, even if it appears in a position where a file name could appear. Therefore, it is unwise to have files whose names begin with ``-''.
The files "" subsection gives the names of files that are built into the program.
A see also .R subsection gives pointers to related information.
A diagnostics subsection discusses the diagnostic indications that may be produced. Messages that are intended to be self-explanatory are not listed.
The bugs "" subsection gives known bugs and sometimes deficiencies. Occasionally the suggested fix is also described.
This section sketches the basic information you need to get started on \s-1UNIX\s+1; how to log in and log out, how to communicate through your terminal, and how to run a program. See ``\s-1UNIX\s+1 for Beginners'' in (USD:1) for a more complete introduction to the system.
Logging in. .R Almost any ASCII terminal capable of full duplex operation and generating the entire character set can be used. You must have a valid user name, which may be obtained from the system administration. If you will be accessing \s-1UNIX\s+1 remotely, you will also need to obtain the telephone number for the system that you will be using.
After a data connection is established, the login procedure depends on what type of terminal you are using and local system conventions. If your terminal is directly connected to the computer, it generally runs at 9600 or 19200 baud. If you are using a modem running over a phone line, the terminal must be set at the speed appropriate for the modem you are using, typically 1200, 2400, or 9600 baud. The half/full duplex switch should always be set at full-duplex. (This switch will often have to be changed since many other systems require half-duplex).
When a connection is established, the system types ``login:''; you type your user name, followed by the ``return'' key. If you have a password, the system asks for it and suppresses echo to the terminal so the password will not appear. After you have logged in, the ``return'', ``new line'', or ``linefeed'' keys will give exactly the same results. A message-of-the-day usually greets you before your first prompt.
If the system types out a few garbage characters after you have established a data connection (the ``login:'' message at the wrong speed), depress the ``break'' (or ``interrupt'') key. This is a speed-independent signal to \s-1UNIX\s+1 that a different speed terminal is in use. The system then will type ``login:,'' this time at another speed. Continue depressing the break key until ``login:'' appears clearly, then respond with your user name.
For all these terminals, it is important that you type your name in lower-case if possible; if you type upper-case letters, \s-1UNIX\s+1 will assume that your terminal cannot generate lower-case letters and will translate all subsequent lower-case letters to upper case.
The evidence that you have successfully logged in is that a shell program will type a prompt (``$'' or ``%'') to you. (The shells are described below under ``How to run a program.'')
For more information, consult tset (1), and stty (1), which tell how to adjust terminal behavior; getty (8) discusses the login sequence in more detail, and tty (4) discusses terminal I/O.
Logging out. .R There are three ways to log out:
By typing ``logout'' or an end-of-file indication (EOT character, control-D) to the shell. The shell will terminate and the ``login:'' message will appear again. You can log in directly as another user by giving a login (1) command. If worse comes to worse, you can simply hang up the phone; but beware - some machines may lack the necessary hardware to detect that the phone has been hung up. Ask your system administrator if this is a problem on your machine.How to communicate through your terminal. .R When you type characters, a gnome deep in the system gathers your characters and saves them in a secret place. The characters will not be given to a program until you type a return (or newline), as described above in Logging in. .R
\s-1UNIX\s+1 terminal I/O is full-duplex. It has full read-ahead, which means that you can type at any time, even while a program is typing at you. Of course, if you type during output, the printed output will have the input characters interspersed. However, whatever you type will be saved up and interpreted in correct sequence. There is a limit to the amount of read-ahead, but it is generous and not likely to be exceeded unless the system is in trouble. When the read-ahead limit is exceeded, the system throws away all the saved characters (or beeps, if your prompt was a ``%'').
The ^U (control-U) character in typed input kills all the preceding characters in the line, so typing mistakes can be repaired on a single line. Also, the delete character (DEL) or sometimes the backspace character (control-H) erases the last character typed. Tset (1) or stty (1) can be used to change these defaults. Successive uses of delete (or backspace) erases characters back to, but not beyond, the beginning of the line. DEL and ^U (control-U) can be transmitted to a program by preceding them with ^V (control-V). (So, to erase ^V (control-V), you need two deletes or backspaces).
An interrupt signal .R is sent to a program by typing ^C (control-C) or the ``break'' key which is not passed to programs. This signal generally causes whatever program you are running to terminate. It is typically used to stop a long printout that you do not want. However, programs can arrange either to ignore this signal altogether, or to be notified when it happens (instead of being terminated). The editor, for example, catches interrupts and stops what it is doing, instead of terminating, so that an interrupt can be used to halt an editor printout without losing the file being edited. The interrupt character can also be changed with tset (1) or stty (1).
It is also possible to suspend output temporarily using ^S (control-S) and later resume output with ^Q (control-Q). Output can be thrown away without interrupting the program by typing ^O (control-O); see tty (4).
The quit "" signal is generated by typing the \s8ASCII\s10 FS character. (FS appears many places on different terminals, most commonly as control-\e or control-\^|\^.) It not only causes a running program to terminate but also generates a file with the core image of the terminated process. Quit is useful for debugging.
Besides adapting to the speed of the terminal, \s-1UNIX\s+1 tries to be intelligent about whether you have a terminal with the newline function or whether it must be simulated with carriage-return and line-feed. In the latter case, all input carriage returns are turned to newline characters (the standard line delimiter) and both a carriage return and a line feed are echoed to the terminal. If you get into the wrong mode, the reset (1) command will rescue you. If the terminal does not appear to be echoing anything that you type, it may be stuck in ``no-echo'' or ``raw'' mode. Try typing ``(control-J)reset(control-J)'' to recover.
Tab characters are used freely in \s-1UNIX\s+1 source programs. If your terminal does not have the tab function, you can arrange to have them turned into spaces during output, and echoed as spaces during input. The system assumes that tabs are set every eight columns. Again, the tset (1) or stty (1) command can be used to change these defaults. Tset (1) can be used to set the tab stops automatically when necessary.
How to run a program; the shells. .R When you have successfully logged in, a program called a shell is listening to your terminal. The shell reads typed-in lines, splits them up into a command name and arguments, and executes the command. A command is simply an executable program. The shell looks in several system directories to find the command. You can also place commands in your own directory and have the shell find them there. There is nothing special about system-provided commands except that they are kept in a directory where the shell can find them.
The command name is always the first word on an input line; it and its arguments are separated from one another by spaces.
When a program terminates, the shell will ordinarily regain control and type a prompt at you to show that it is ready for another command.
The shells have many other capabilities, that are described in detail in sections sh (1) and csh (1). If the shell prompts you with ``$'', then it is an instance of sh (1), the original \s-1UNIX\s+1 shell. If it prompts with ``%'' then it is an instance of csh (1), a shell written at Berkeley. The shells are different for all but the most simple terminal usage. Most users at Berkeley choose csh (1) because of the history mechanism and the alias feature, that greatly enhance its power when used interactively. Csh also supports the job-control facilities; see csh (1) or the Csh introduction in USD:4 for details.
You can change from one shell to the other by using the chpass (1) command, which takes effect at your next login.
The current directory. .R \s-1UNIX\s+1 has a file system arranged as a hierarchy of directories. When the system administrator gave you a user name, they also created a directory for you (ordinarily with the same name as your user name). When you log in, any file name you type is by default in this directory. Since you are the owner of this directory, you have full permission to read, write, alter, or destroy its contents. Permissions to have your will with other directories and files will have been granted or denied to you by their owners. As a matter of observed fact, few \s-1UNIX\s+1 users protect their files from perusal by other users.
To change the current directory (but not the set of permissions you were endowed with at login) use cd (1).
Path names. .R To refer to files not in the current directory, you must use a path name. Full path names begin with ``/\|'', the name of the root directory of the whole file system. After the slash comes the name of each directory containing the next sub-directory (followed by a ``/\|'') until finally the file name is reached. For example, /\^var/\^tmp/\^filex .R refers to the file filex .R in the directory tmp; tmp .R is itself a subdirectory of var; var .R springs directly from the root directory.
If your current directory has subdirectories, the path names of files therein begin with the name of the subdirectory with no prefixed ``/\|''.
A path name may be used anywhere a file name is required.
Important commands that modify the contents of files are cp (1), mv (1), and rm (1), which respectively copy, move (i.e. rename) and remove files. To find out the status of files or directories, use ls (1). See mkdir (1) for making directories and rmdir (1) for destroying them.
For a fuller discussion of the file system, see ``A Fast File System for \s-1UNIX\s+1'' (SMM:5) by McKusick, Joy, Leffler, and Fabry. It may also be useful to glance through PRM section 2, that discusses system calls, even if you do not intend to deal with the system at that level.
Writing a program. .R To enter the text of a source program into a \s-1UNIX\s+1 file, use the standard display editor vi (1) or its \s-1WYSIWYG\s+1 counterparts jove (1) and emacs (1). (The old standard editor ed (1) is also available.) The principle language in \s-1UNIX\s+1 is provided by the C compiler cc (1). User contributed software in the latest release of the system supports the programming languages perl and C++. After the program text has been entered through the editor and written to a file, you can give the file to the appropriate language processor as an argument. The output of the language processor will be left on a file in the current directory named ``a.out''. If the output is precious, use mv (1) to move it to a less exposed name after successful compilation.
When you have finally gone through this entire process without provoking any diagnostics, the resulting program can be run by giving its name to the shell in response to the shell (``$'' or ``%'') prompt.
Your programs can receive arguments from the command line just as system programs do, see ``\s-1UNIX\s+1 Programming - Second Edition'' (PSD:4), or for a more terse description execve (2).
Text processing. .R Almost all text is entered through an editor such as vi (1), jove (1), or emacs (1). The commands most often used to write text on a terminal are: cat (1), more (1), and nroff (1).
The cat (1) command simply dumps \s8ASCII\s10 text on the terminal, with no processing at all. More (1) is useful for preventing the output of a command from scrolling off the top of your screen. It is also well suited to perusing files. Nroff (1) is an elaborate text formatting program. Used naked, it requires careful forethought, but for ordinary documents it has been tamed; see me (7) and ms (7).
Groff (1) converts documents to postscript for output to a Laserwriter or Phototypesetter. It is similar to nroff (1), and often works from exactly the same source text. It was used to produce this manual.
Script (1) lets you keep a record of your session in a file, which can then be printed, mailed, etc. It provides the advantages of a hard-copy terminal even when using a display terminal.
Status inquiries. .R Various commands exist to provide you with useful information. w (1) prints a list of users currently logged in, and what they are doing. date (1) prints the current time and date. ls (1) will list the files in your directory or give summary information about particular files.
Surprises. .R Certain commands provide inter-user communication. Even if you do not plan to use them, it would be well to learn something about them, because someone else may aim them at you.
To communicate with another user currently logged in, write (1) or talk (1) is used; mail (1) will leave a message whose presence will be announced to another user when they next log in. The write-ups in the manual also suggest how to respond to the these commands if you are a target.
If you use csh (1) the key ^Z (control-Z) will cause jobs to ``stop''. If this happens before you learn about it, you can simply continue by saying ``fg'' (for foreground) to bring the job back.
We hope that you will come to enjoy using the BSD system. Although it is very large and contains many commands, you can become very productive using only a small subset of them. As your needs expand to doing new tasks, you will almost always find that the system has the facilities that you need to accomplish them easily and quickly.
Most importantly, the source code to the BSD system is cheaply available to anyone that wants it. On many BSD systems, it can be found in the directory /\|usr/\|src . You may simply want to find out how something works or fix some important bug without waiting months for your vendor to respond. It is also particularly useful if you want to grab another piece of code to bootstrap a new project. Provided that you retain the copyrights and acknowledgements at the top of each file, you are free to redistribute your work for fun or profit. Naturally, we hope that you will allow others to also redistribute your code, though you are not required to do so unless you use copyleft code (which is primarily found in the software contributed from the Free Software Foundation and is clearly identified).
Good luck and enjoy BSD. \& .EH '''' .OH '''' .bp .OH '\s10Manual Pages''- % -\s0' .EH '\s10- % -''Manual Pages\s0' .EF '\s10\\\\*(Dt''\\\\*(Ed\s0' .OF '\s10\\\\*(Ed''\\\\*(Dt\s0' .nr PS 10 .nr VS 11.5
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