computer science

List of Plan 9 applications

List of Plan 9 applications is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand List of Plan 9 applications rather than just read about it. In short: This is a list of Plan 9 programs. Many of these programs are very similar to the UNIX programs with the same name, others are to be found only on Plan 9.

Key takeaways

List of Plan 9 applications belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect List of Plan 9 applications to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of List of Plan 9 applications from memory before moving on to harder problems.

Reference excerpt

This is a list of Plan 9 programs. Many of these programs are very similar to the UNIX programs with the same name, others are to be found only on Plan 9. Others again share only the name, but have a different behaviour.

System software

General user dd – convert and copy a file date – date and time echo – print arguments file – determine file type ns – display namespace plumb – send message to plumber plumber – interprocess messaging rc – rc is the Plan 9 shell rio – the new Plan 9 windowing system 8½ – the old Plan 9 windowing system [1] uptime – show how long the system has been running

System management

Processes and tasks management time – time a command kill, slay, broke – print commands to kill processes sleep – suspend execution for an interval ps – process status psu – process status information about processes started by a specific user

User management and support passwd, netkey, iam – change user password who – who is using the machine man, lookman – print or find pages of this manual

File system and server /boot/boot – connect to the root file server fossil/fossil, fossil/flchk, fossil/flfmt, fossil/conf, fossil/last – archival file server history – print file names from the dump users – file server user list format vac – create a vac archive on Venti venti/buildindex, venti/checkarenas, venti/checkindex, venti/conf, venti/copy, venti/fmtarenas, venti/fmtindex, venti/fmtisect, venti/rdarena, venti/rdarenablocks, venti/read, venti/wrarenablocks, venti/write – Venti maintenance and debugging commands venti/venti, venti/sync – an archival block storage server yesterday, diffy – print file names from the dump

Hardware devices setrtc – set real time clock (RTC) on PC hardware

Files and text

Filesystem utilities chgrp – change file group chmod – change mode cp, fcp, mv – copy, move files du – disk usage ls, lc – list contents of directory mkdir – make a directory bind, mount, umount – change name space pwd, pbd – working directory rm – remove files touch – set modification date of a file

Archivers and compression ar – archive and library maintainer gzip, gunzip, bzip2, bunzip2, compress, uncompress, zip, unzip – compress and expand data tar – archiver

Text processing awk – pattern-directed scanning and processing language cat, read – catenate files cmp – compare two files diff – differential file comparator doc2txt, xls2txt – extract printable strings from Microsoft Office documents doctype – intuit command line for formatting a document fmt, htmlfmt – simple text formatters freq – print histogram of character frequencies grep – search a file for a pattern idiff – interactive diff mc – multicolumn print p – paginate pr – print file sed – stream editor spell, sprog – find spelling errors split – split a file into pieces tail – deliver the last part of a file tcs – translate character sets tr – translate characters wc – word count xd – hex, octal, decimal or ASCII dump of file

Editors acme – interactive text editor and shell ed – text editor sam – screen editor with structural regular expressions

Communication, networking and remote access con, telnet, rx, xms, xmr – remote login, execution, and XMODEM file transfer cpu – connection to CPU server dial/at, dial/drain, dial/expect, dial/pass – dialer scripting tools netstat – summarize network connections replica/changes, replica/pull, replica/push, replica/scan – client–server replica management ssh, sshnet, scp, aux/sshserve – secure login and file copy from/to Unix or Plan 9 tel, iwhois – look in phone book vncs, vncv – remote frame buffer server and viewer for Virtual Network Computing (VNC)

Email and news programs faces, seemail, vwhois – mailbox interface mail – mail and mailboxes news – print news items upas/filter, upas/list, upas/deliver, upas/token, upas/vf – filtering mail upas/fs – mail file server upas/marshal – formatting and sending mail upas/ml, upas/mlmgr, upas/mlowner – unmoderated mailing lists upas/nedmail – reading mail upas/scanmail, upas/testscan – spam filters upas/send – mail routing and delivery upas/smtp, upas/smtpd – mail transport

Network system services ip/dhcpd, ip/dhcpleases, ip/rarpd, ip/tftpd – Internet booting aux/listen – listen for calls on a network device ndb/query, ndb/mkhash, ndb/mkdb, ndb/cs, ndb/csquery, ndb/dns, ndb/dnsquery, ndb/ipquery, ndb/dnsdebug, ndb/mkhosts – network database upas/pop3, ip/imap4d – mail servers aux/timesync – NTP client

Network utilities aan – always available network ip/ipconfig, ip/rip – Internet configuration and routing ip/telnetd, ip/rlogind, ip/rexexec, ip/ftpd – Internet remote access daemons ip/ping, ip/gping, ip/traceroute, ip/hogports – probe the Internet snoopy – spy on network packets ip/udpecho – echo UDP packets

Security auth/aescbc, ipso, auth/secstore – secstore commands auth/changeuser, auth/wrkey, auth/convkeys, auth/convkeys2, auth/printnetkey, auth/status, auth/authsrv, auth/guard.srv, auth/login, auth/disable, auth/enable – maintain authentication databases auth/factotum, auth/fgui – authentication agent auth/secstored, auth/secuser – secstore commands delkey – delete keys from factotum

Programming tools

Compilers and programming tools 0a, 1a, 2a, 5a, 7a, 8a, ka, qa, va – assemblers 0c, 1c, 2c, 5c, 7c, 8c, kc, qc, vc – C compilers 0l, 1l, 2l, 5l, 7l, 8l, kl, ql, vl – loaders acid, truss, trump – debugger bc – arbitrary–precision arithmetic language cb – C program beautifier cpp – C language preprocessor ktrace – interpret kernel stack dumps leak, kmem – help find memory leaks mk, membername – maintain (make) related files patch – simple patch creation and tracking system pcc – APE C compiler driver strip – remove symbols from binary files syscall – test a system call yacc – yet another compiler-compiler

Application software

Web browsers abaco – a "lame" text-based and graphical web browser i – rough web browser, based on charon links – a text-based and graphical web browser mothra – a very basic web browser netsurf - an open-source browser with html, javascript, and css support

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with List of Plan 9 applications

Start with the simplest possible case. Write down what List of Plan 9 applications claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to List of Plan 9 applications before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about List of Plan 9 applications ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of List of Plan 9 applications

In research: List of Plan 9 applications appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses List of Plan 9 applications in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: List of Plan 9 applications is common in secondary-school and first-year university syllabi. It links to neighbouring topics Lists of software, Plan 9 from Bell Labs, System administration, so understanding it makes those chapters shorter.
In everyday life: Look for List of Plan 9 applications outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study List of Plan 9 applications in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what List of Plan 9 applications means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain List of Plan 9 applications out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is List of Plan 9 applications in simple terms?

This is a list of Plan 9 programs. Many of these programs are very similar to the UNIX programs with the same name, others are to be found only on Plan 9.

Why does List of Plan 9 applications matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study List of Plan 9 applications?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on List of Plan 9 applications.