hel1

unix v7是最后一个广泛发布的研究型UNIX版本

.SH
B.  Hardware
.PP
The
7th edition
.UC UNIX
operating system
runs on
a DEC PDP-11/45 or 11/70*
.FS
*PDP is a Trademark of Digital Equipment Corporation.
.FE
with at least the following equipment:
.IP
128K to 2M words of managed memory; parity not used.
.IP
disk: RP03, RP04, RP06, RK05 (more than 1 RK05) or equivalent.
.IP
console typewriter.
.IP
clock: KW11-L or KW11-P.
.LP
The following equipment is strongly recommended:
.IP
communications controller such as DL11 or DH11.
.IP
full duplex 96-character ASCII terminals.
.IP
9-track tape or extra disk for system backup.
.LP
The system is normally distributed on 9-track tape.
The minimum memory and disk space specified is enough to run
and maintain
.UC UNIX .
More will be needed to keep all source on line, or to handle
a large number of users,
big data bases, diversified complements of devices, or large
programs.
The resident code
occupies 12-20K words depending
on configuration;
system data occupies 10-28K words.
.PP
There is no commitment to provide 7th edition
.UC UNIX
on PDP-11/34, 11/40 and 11/60 hardware.
.SH
C.  Software
.PP
Most of the programs available as
.UC UNIX
commands are listed.
Source code and printed manuals are 
distributed for all of the listed software
except games.
Almost all of the code is written in C.
Commands are self-contained and do not require extra setup
information,
unless specifically noted as ``interactive.''
Interactive programs can be made to run from a prepared script
simply by redirecting input.
Most programs intended for interactive use
(e.g., the editor) 
allow for an escape to
command level (the Shell).
Most file processing commands
can also go from standard input to standard output
(``filters'').
The piping facility of the Shell may be used
to connect such filters directly to the input or output
of other programs.
.NH
Basic Software
.PP
This
includes the time-sharing operating
system with utilities, a machine language assembler and a 
compiler for the programming language C\(emenough
software to
write and run new applications
and to maintain or modify
.UC UNIX
itself.
.NH 2
Operating System
.sh UNIX
The basic resident code
on which everything else depends.
Supports the system calls, and maintains the file system.
A general description of
.UC UNIX
design
philosophy and system facilities appeared in
the Communications of the ACM, July, 1974.
A more extensive survey is in the Bell System Technical Journal
for July-August 1978.
Capabilities include:
.op
Reentrant code for user processes.
.op
Separate instruction and data spaces.
.op
``Group'' access permissions for cooperative projects,
with overlapping memberships.
.op
Alarm-clock timeouts.
.op
Timer-interrupt sampling and interprocess monitoring
for debugging and measurement.
.OP
Multiplexed I/O for machine-to-machine communication.
.sh DEVICES
All I/O is logically synchronous.
I/O devices are simply files in the file system.
Normally, invisible buffering makes all physical
record structure and device characteristics transparent and exploits the
hardware's ability to do overlapped I/O.
Unbuffered physical record
I/O is available for unusual applications.
Drivers for these devices are
available; others can be easily written:
.op
Asynchronous interfaces: DH11, DL11.
Support for most common ASCII terminals.
.op
Synchronous interface: DP11.
.op
Automatic calling unit interface: DN11.
.op
Line printer: LP11.
.op
Magnetic tape: TU10 and TU16.
.op
DECtape: TC11.
.op
Fixed head disk: RS11, RS03 and RS04.
.op
Pack type disk: RP03, RP04, RP06;
minimum-latency seek scheduling.
.op
Cartridge-type disk: RK05, one or more physical devices per
logical device.
.op
Null device.
.op
Physical memory of PDP-11, or mapped memory in resident system.
.op
Phototypesetter: Graphic Systems System/1 through DR11C.
.sh BOOT
Procedures to get
.UC UNIX
started.
.sh MKCONF
Tailor device-dependent system code to hardware configuration.
As distributed,
.UC UNIX
can 
be brought up directly on any acceptable CPU
with any acceptable disk, any sufficient amount of core,
and either clock.
Other changes, such as optimal
assignment of directories to devices, inclusion of floating
point simulator, or installation of device names in file system,
can then be made at leisure.
.NH 2
User Access Control
.LP
.sh LOGIN
Sign on as a new user.
.op
Verify password and establish user's 
individual and group (project) identity.
.op
Adapt to characteristics of terminal.
.op
Establish working directory.
.op
Announce presence of mail (from MAIL).
.op
Publish message of the day.
.op
Execute user-specified profile.
.op
Start command interpreter or other initial program.
.sh PASSWD
Change a password.
.op
User can change his own password.
.op
Passwords are kept encrypted for security.
.sh NEWGRP
Change working group (project).
Protects against unauthorized changes to projects.
.NH 2
Terminal Handling
.LP
.sh TABS
Set tab stops appropriately for specified terminal type.
.sh STTY
Set up options for optimal control of a terminal.
In so far as they are deducible from the input, these
options are set automatically by LOGIN.
.op
Half vs. full duplex.
.op
Carriage return+line feed vs. newline.
.op
Interpretation of tabs.
.op
Parity.
.op
Mapping of upper case to lower.
.op
Raw vs. edited input.
.op
Delays for tabs, newlines and carriage returns.
.NH 2
File Manipulation
.LP
.sh CAT
Concatenate one or more files onto standard output.
Particularly used for unadorned printing, for
inserting data into a pipeline,
and for buffering output that comes in dribs and drabs.
Works on any file regardless of contents.
.sh CP
Copy one file to another,
or a set of files to a directory.
Works on any file regardless of contents.
.sh PR
Print files with title, date, and page number on every page.
.op
Multicolumn output.
.op
Parallel column merge of several files.
.sh LPR
Off-line print.
Spools arbitrary files to the line printer.
.sh CMP
Compare two files and report if different.
.sh TAIL
Print last
.I n
lines of input
.op
May print last
.I n
characters, or from
.I n
lines or characters to end.
.sh SPLIT
Split a large file into more manageable pieces.
Occasionally necessary for editing (ED).
.sh DD
Physical file format translator,
for exchanging data with foreign
systems, especially IBM 370's.
.sh SUM
Sum the words of a file.
.NH 2
Manipulation of Directories and File Names
.LP
.sh RM
Remove a file.
Only the name goes away if any other names are linked to the file.
.OP
Step through a directory deleting files interactively.
.OP
Delete entire directory hierarchies.
.sh LN
``Link'' another name (alias) to an existing file.
.sh MV
Move a file or files.
Used for renaming files.
.sh CHMOD
Change permissions on one or more files.
Executable by files' owner.
.sh CHOWN
Change owner of one or more files.
.sh CHGRP
Change group (project) to which a file belongs.
.sh MKDIR
Make a new directory.
.sh RMDIR
Remove a directory.
.sh CD
Change working directory.
.sh FIND
Prowl the directory
hierarchy finding
every file that meets
specified criteria.
.op
Criteria include:
.in +2
.nf
name matches a given pattern,
creation date in given range,
date of last use in given range,
given permissions,
given owner,
given special file characteristics,
boolean combinations of above.
.in -2
.fi
.op
Any directory may be considered to be the root.
.op
Perform specified command on each file found.
.NH 2
Running of Programs
.LP
.sh SH
The Shell, or command language interpreter.
.op
Supply arguments to and run any executable program.
.op
Redirect standard input, standard output, and standard error files.
.op
Pipes:
simultaneous execution with output of one process connected
to the input of another.
.OP
Compose compound commands using:
.in+2
if ... then ... else,
.br
case switches,
.br
while loops,
.br
for loops over lists,
.br
break, continue and exit,
.br
parentheses for grouping.
.in -2
.op
Initiate background processes.
.op
Perform Shell programs, i.e., command scripts with
substitutable arguments.
.op
Construct argument lists from all file names
satisfying specified patterns.
.OP
Take special action on traps and interrupts.
.OP
User-settable search path for finding commands.
.OP
Executes user-settable profile upon login.
.OP
Optionally announces presence of mail as it arrives.
.op
Provides variables and parameters with default setting.
.sh TEST
Tests for use in Shell conditionals.
.op
String comparison.
.op
File nature and accessibility.
.op
Boolean combinations of the above.
.sh EXPR
String computations for calculating command arguments.
.OP
Integer arithmetic
.OP
Pattern matching
.sh WAIT
Wait for termination of asynchronously running processes.
.sh READ
Read a line from terminal,
for interactive Shell procedure.
.sh ECHO
Print remainder of command line.
Useful for diagnostics or prompts in Shell programs,
or for inserting data into a pipeline.
.sh SLEEP
Suspend execution for a specified time.
.sh NOHUP
Run a command immune to hanging up the terminal.
.sh NICE
Run a command in low (or high) priority.
.sh KILL
Terminate named processes.
.sh CRON
Schedule regular actions at specified times.
.op
Actions are arbitrary programs.
.op
Times are
conjunctions of month, day of month, day of week, hour