hel2

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

.h0 "\na.\n+b User Access Control"
.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
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 better security.
.sh NEWGRP
Change working group (project).
Protects against changes to unauthorized projects.
.h0 "\na.\n+b File Manipulation"
.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.
.op
Usable as filter.
.sh CP
Copy one file to another.
Works on any file without distinction as to contents.
.sh PR
Print files with title, date, and page number on every page.
.op
Multicolumn output.
.op
Parallel column merge of several files.
.op
Usable as a filter.
.sh OPR
Off line print.
Spools arbitrary files to the line printer.
.op
Usable as a filter.
.sh SPLIT
Split a large file into more manageable pieces.
Is occasionally necessary for editing (ED).
..
.sh ED
Interactive context editor.
Can work on single lines, blocks of lines, or all pattern-selected
lines in a given range.
.op
Finds lines by number or pattern.
.op
Random access to lines.
.op
Add, delete, change, copy or move lines.
.op
Permute or split contents of a line.
.op
Replace one or all instances of a pattern within a line.
.op
Combine or split files.
.op
Escape to Shell (U\s8NIX\s10 command language) during editing.
.ne3
.op
Patterns may include:
.in +2
specified characters,
.br
don't care characters,
.br
choices among characters,
.br
repetitions of above,
.br
beginning of line,
.br
end of line.
.in -2
.op
All operations may be done globally on
every pattern-selected line in a given range.
.sh Manual
Introductory manual for ED.
.sh DD
Physical file format translator,
for exchanging data with foreign
systems, especially OS/360.
.sh STTY
Sets 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.
.h0 "\na.\n+b Manipulation of Directories and File Names"
.sh RM
Remove a file.
Only the name goes away if any other names are linked to the file.
.sh LN
\*(lqLink\*(rq another name (alias) to an existing file.
.sh MV
Move a file.
.op
Used for renaming files or directories.
.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 CHDIR
Change working directory.
.sh FIND
Prowl the directory
hierarchy finding
every file that meets
specified criteria.
.op
These criteria are understood:
.in +2
.nf
spelling of name matches a given pattern,
creation date in given range,
date of last use in given range,
permissions,
owner,
characteristics of device files,
boolean combinations of above.
.in -2
.fi
.op
Any directory may be considered to be the root.
.op
Specified commands may be performed on every file found.
.sh DSW
Interactively step through a directory,
deleting or keeping files.
.h0 "\na.\n+b Running of Programs"
.sh SH
The Shell, or command language interpreter.
Provides \*(lqbackground\*(rq and macro capability when
run with a file of commands as input.
.br
.op
Any executable object file is automatically a command.
.op
Redirect standard input or standard output.
.op
Operators to compose compound commands:
.in+2
`;' for sequential execution,
.br
`|' for functional composition with output of one
command taken directly as input to another running simultaneously,
.br
`&' for asynchronous operation,
.br
parentheses for grouping.
.in -2
.op
Substitutable arguments.
.op
Construction of argument lists from all file names
satisfying specified patterns.
.op
Collects command usage statistics.
.sh IF
A conditional statement for Shell programs.
.op
String comparison.
.op
Querying file accessibility.
.sh GOTO
A \*(lqgo-to\*(rq statement for Shell programs.
.sh WAIT
Wait for termination of asynchronously running processes.
.sh EXIT
Terminate a Shell program.
Useful with IF.
.sh ECHO
Print remainder of command line.
Useful for diagnostic or prompting data 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
A table of actions to be taken at specified times.
.op
Actions are arbitrary Shell (SH) scripts.
.op
Times are
conjunctions of month, day of month, day of week, hour
and minute.
Ranges are specifiable for each.
.sh TEE
Pass data between processes and divert a copy into a file.
Used as a filter.
.h0 "\na.\n+b Status Inquiries"
.sh LS
List the names of one, several, or all files in one or more directories.
.op
Alphabetic or temporal sorting, up or down.
.op
Optional information:
size,
owner,
group,
date last modified,
date last accessed,
permissions,
i-node number.
.sh FILE
Tries to determine 
what kind of information is in a file by consulting
the file system index and by reading the file itself.
.sh DATE
System date routine.
Has considerable knowledge
of calendric and horological peculiarities.
.op
Print present date, day of week, local time.
.op
May set U\s8NIX\s10's idea of date and time.
.sh DF
Report amount of free space on file system devices.
.sh DU
Print a summary of total space occupied by all files in a hierarchy.
.sh WHO
Tell who's on the system.
.op
List of presently logged in users,
ports and times on.
.op
Optional history of all logins and logouts.
.sh PS
Report on all active processes attached to a terminal.
.op
Gives all commands being executed.
.op
Can also report on other terminals.
.op
Extended status information available:
.in+2
.nf
state and scheduling info,
priority,
attached terminal,
what it's waiting for,
size.
.fi
.in -2
.fi
.sh TTY
Find name of your terminal.
.sh PWD
Print name of your working directory.
.sh PFE
Print type of last floating exception.
.h0 "\na.\n+b Backup and Maintenance"
.sh MOUNT
Attach a device containing
a file system to
the tree of directories.
Protects against nonsense arrangements.
.sh UMOUNT
Remove the file system contained on a device
from the tree of directories.
Protects against removing a busy device.
.sh MKFS
Make a new file system on a device.
.sh MKNOD
Make an i-node (file system entry) for a special file.
Special files are
physical devices,
virtual devices, physical memory, etc.
.sh TP
Manage file archives on magnetic tape or DEC tape.
.op
Collect files into an archive.
.op
Update DECtape archive by date.
.op
Replace or delete DECtape files.
.op
Table of contents.
.op
Retrieve from archive.
.sh DUMP
Dump the file system
stored on a specified device, selectively by date, or indiscriminately.
.sh RESTOR
Restore a dumped file system,
or selectively retrieve parts thereof.
.sh SU
Temporarily become the super user with all the rights and privileges
thereof.
Requires a password.
.sh DCHECK
.sh ICHECK
.sh NCHECK
.sp -2
Check consistency of file system.
.op
Gross statistics:
.in +2
.nf
number of files,
number of directories,
number of special files,
spaced used,
space free.
.in -2
.fi
.op
Report of duplicate use of space.
.op
Retrieval of lost space.
.op
Report of inaccessible files.
.op
Check consistency of directories.
.op
List names of all files.
.sh CLRI
Peremptorily expunge a file and its space from a file system.
Used in putting damaged file systems together again.
.sh SYNC
Force all outstanding I/O on the system to completion.
Used to shut down gracefully.
.h0 "\na.\n+b Accounting"
.in0
.sp
These routines use floating point.
The timing information on which the reports are based can be
manually cleared or shut off completely.
.sh AC
Publish cumulative connect time report.
.op
Connect time by user or by day.
.op
For all users or for selected users.
.sh SA
Publish Shell accounting
report.
Gives usage information on each command executed.
.op
Number of times used.
.op
Total system time, user time and elapsed time.
.op
Optional averages and percentages.
.op
Sorting on various fields.
.h0 "\na.\n+b Inter-user Communication"
.sh MAIL
Mail a message to one or more users.
Also used to read and dispose of incoming mail.
The presence of mail is announced by LOGIN.
.sh WRITE
Establish direct terminal communication with another user.
.sh WALL
Write to all users.
.sh MESG
Inhibit receipt of messages from WRITE and WALL.