| Process / IPC | 
|---|
| arg | arg - parse program arguments | 
| command | command - command interface | 
| debug | debug - process debugging | 
| env | env - environment module | 
| exception | exception - Exception module | 
| itslib | itslib - test library | 
| lock | lock - thread locking. | 
| plumbmsg | plumbmsg - plumbing message module | 
| prof | profile - profiling library | 
| sh | Sh - module interface to the shell | 
| sys-pctl | pctl - process control | 
| sys-pipe | pipe - create an interprocess channel | 
| wait | wait - wait for child process to exit | 
| Date / Time | 
|---|
| daytime | daytime: text, filet, gmt, local, now, time, tm2epoch - time conversions | 
| sys-millisec | millisec - millisecond timer | 
| sys-sleep | sleep - delay | 
| timers | timers - interval timers | 
| Data structures | 
|---|
| bloomfilter | Bloomfilter - Bloom filters | 
| dict | dict - list of string pairs | 
| hash | hash, HashTable - hash table | 
| sets | Sets - sets of non-negative integers | 
| stringinttab | stringinttab - string table lookup module | 
| Data conversion | 
|---|
| convcs | Convcs, Btos, Stob - character set conversion suite | 
| crc | crc - Crc module | 
| encoding | Encoding: enc, dec - encoding and decoding of byte arrays as text | 
| filter | filter - data processing interface | 
| filter-deflate | deflate, inflate - data compression filters | 
| filter-slip | slip - SLIP data framing protocol | 
| geodesy | geodesy - Geodesy module | 
| ida | Ida: Frag, fragment, consistent, reconstruct - information dispersal algorithm | 
| regex | regex - regular expression recognizer module | 
| string | string: append, drop, in, prefix, quoted, splitl, splitr, splitstrl, splitstrr, take, tobig, toint, tolower, toupper, unquoted - string operations | 
| sys-byte2char | byte2char, char2byte - convert between bytes and characters | 
| sys-utfbytes | utfbytes - compute UTF length of complete Unicode characters in a UTF byte sequence | 
| sys-tokenize | tokenize - split string into words | 
| Data format | 
|---|
| format | format - structured data interchange | 
| json | json: readjson, writejson, JValue - read, write and represent values in JavaScript Object Notation | 
| rfc822 | rfc822 - RFC822 mail format helpers | 
| sexprs | Sexprs: Sexp - S-expressions | 
| ubfa | ubfa: readubf, writeubf, UValue - read, write and represent values in a UBF(A) data transport encoding | 
| w3c-css | w3c-css - cascading style sheet parser | 
| w3c-uris | w3c-uris - uniform resource identifiers | 
| w3c-xpointers | w3c-xpointers - parser for XPointers framework including XPath | 
| xml | xml - XML navigation | 
| File format / Database | 
|---|
| attrdb | attrdb - database of attribute-value pairs | 
| cfg | Cfg, Record, Tuple, Attr - configuration file parser | 
| csv | csv - comma-separated values | 
| dis | dis - read Dis object files | 
| dbm | Dbm: Dbf, init - data base with hashed indexing | 
| fsproto | FSproto: readprotofile, readprotostring - read file system prototype file | 
| palmfile | Palmfile: Categories, DBInfo, Doc, Entry, Pfile, Record - read Palmâ„¢ file formats | 
| registries | registries - access services registry | 
| translate | translate: opendict, opendicts, mkdictname - translation dictionaries | 
| I/O | 
|---|
| bufio | bufio, bufiofill - buffered input/output module | 
| bufio-chanfill | bufio: chanfill - buffered I/O interface to named channel | 
| diskblocks | Diskblocks: Block, Disk, tempfile - temporary storage of variable-sized blocks | 
| sys-print | print, aprint, fprint, sprint - print formatted output | 
| sys-read | read, write, pread, pwrite, stream - read or write file | 
| sys-seek | seek - change file offset | 
| Path | 
|---|
| complete | complete - file name completion | 
| names | Names: basename, cleanname, dirname, elements, isprefix, pathname, relative, rooted - file name manipulation | 
| filepat | filepat: expand, match - file pattern matching | 
| newns | newns - build a new name space from a description file | 
| readdir | readdir - read directory and sort files | 
| sys-bind | bind, mount, unmount - change file name space | 
| sys-chdir | chdir - change working directory | 
| sys-dirread | dirread - read directory | 
| sys-dup | dup, fildes - duplicate an open file descriptor | 
| sys-fd2path | fd2path - return file name associated with file descriptor | 
| sys-open | open, create - open a file for reading or writing, create file | 
| sys-remove | remove - remove a file | 
| sys-stat | fstat, fwstat, stat, wstat - get and put file status | 
| workdir | workdir - get the current working directory | 
| Styx | 
|---|
| styx | Styx: Rmsg, Tmsg, dir2text, istmsg, packdir, packdirsize, readmsg, qid2text, unpackdir - interface to Styx file protocol | 
| styxconv | styxconv - convert between old and new Styx | 
| styxpersist | styxpersist - persistent Styx connection | 
| styxservers | styxservers - Styx server implementation assistance | 
| styxservers-nametree | Styxservers: nametree - hierarchical name storage for use with Styxservers. | 
| sys-export | export - export a name space | 
| sys-fauth | fauth - set up authentication on a file descriptor to a file server | 
| sys-file2chan | file2chan - create file connected to Limbo channel | 
| sys-fversion | fversion - initialize Styx connection and negotiate version | 
| sys-iounit | iounit - return size of atomic I/O unit for file descriptor | 
| Network | 
|---|
| dhcpclient | Dhcpclient: Bootconf, Lease, bootp, dhcp, applycfg, removecfg - client's side of dynamic host configuration protocol | 
| ether | ether - Ethernet address manipulation | 
| ip | IP - Internet Protocol addresses and interfaces | 
| pop3 | pop3 - Post Office Protocol | 
| smtp | smtp - Simple Mail Transfer Protocol | 
| srv | srv - network name and address translation when hosted | 
| sys-dial | announce, dial, listen - make network connections | 
| tftp | tftp - Trivial File Transfer Protocol | 
| venti | Venti - access to Venti content-addressed filestore. | 
| virgil | virgil - pose question to name resolver | 
| Math | 
|---|
| math-0intro | Math: intro - elementary numerics | 
| math-elem | Math: cbrt, sqrt, pow, pow10, hypot, exp, expm1, log, log10, log1p, cos, cosh, sin, sinh, tan, tanh, acos, asin, acosh, asinh, atan, atanh, atan2, lgamma, erf, erfc, j0, j1, y0, y1, jn, yn - elementary functions of applied mathematics | 
| math-export | Math: export_int, export_real, export_real32, import_int, import_real, import_real32 - conversion to and from external representation | 
| math-fp | math-fp - floating point | 
| math-linalg | Math: dot, norm1, norm2, iamax, gemm, sort - linear algebra primitives | 
| rand | rand - pseudo random number generation | 
| security-random | random: randomint, randombuf - random number generation | 
| Misc | 
|---|
| 0intro | intro - introduction to Limbo modules for the Inferno system | 
| alphabet-intro | Alphabet - experimental typed shell | 
| disks | disks: Disk, PCpart, readn, chstext - generic disk and partition interface | 
| scsiio | ScsiIO: Scsi - SCSI device operations | 
| sys-0intro | Sys: intro - introduction to the | 
| sys-self | SELF - reference self as a compatible module type | 
| sys-werrstr | werrstr - set the system error string | 
| Spree | 
|---|
| spree | Spree - distributed interactive sessions. | 
| spree-allow | Allow - filter client actions | 
| spree-cardlib | Cardlib - support for card games in Spree engines. | 
| spree-gather | Gatherengine - module interface for pre-assembled groups. | 
| spree-objstore | Objstore - support for object archiving in Spree engines. | 
| Security | 
|---|
| asn1 | asn1: decode, encode - ASN.1 (X.208), BER (X.209) encoding | 
| factotum | Factotum: mount, proxy, rpc - client interface to factotum | 
| keyring-0intro | Keyring intro - introduction to the | 
| keyring-auth | keyring: auth, readauthinfo, writeauthinfo - authenticate a connection | 
| keyring-certtostr | keyring: certtostr, pktostr, sktostr, strtocert, strtopk, strtosk - encryption key conversion functions | 
| keyring-crypt | keyring: aessetup, aescbc, dessetup, descbc, desecb, ideasetup, ideacbc, ideaecb - data encryption | 
| keyring-gensk | keyring: genSK, genSKfromPK, sktopk, dhparams - generate keys | 
| keyring-getmsg | keyring: getmsg, sendmsg, senderrmsg - send and receive messages on undelimited streams | 
| keyring-getstring | keyring: getstring, putstring, getbytearray, putbytearray, puterror - exchange data on delimited streams | 
| keyring-ipint | keyring: IPint - `infinite' precision integer utility functions | 
| keyring-rc4 | keyring: rc4setup, rc4, rc4skip, rc4back - RC4 encryption | 
| keyring-sha1 | keyring: sha1, md4, md5, hmac_sha1, hmac_md5, sign, verify - cryptographic digests and digital signatures | 
| keyset | keyset - find authentication keys matching a signer | 
| secstore | secstore - fetch data from Plan 9's secure storage service | 
| security-0intro | intro - introduction to security | 
| security-auth | Auth: init, client, server - authenticated connections between client and server | 
| security-login | login - verify credentials | 
| security-ssl | ssl: connect, secret - interface to the Secure Sockets Layer | 
| spki | SPKI: Cert, Hash, Key, Name, Seqel, Signature, Subject, Toplev, Valid - simple public key infrastructure | 
| spki-verifier | verifier: verify - verify sequence of SPKI elements | 
| Graphics and User Interfaces | 
|---|
| devpointer | devpointer - I/O interface for the pointer device | 
| dialog | dialog: prompt, getstring - basic dialog boxes | 
| dividers | Dividers - user-draggable tk dividing bars | 
| draw-0intro | draw - basic graphics facilities module | 
| draw-context | Context - graphics environment | 
| draw-display | Display - connection to draw device | 
| draw-example | draw: example - simple program illustrating image primitives | 
| draw-font | Font - character images for Unicode text | 
| draw-image | Image - pictures and drawing | 
| draw-point | Point - coordinate position | 
| draw-pointer | Pointer - state of a pointer device such as a mouse | 
| draw-rect | Rect - rectangular portion of the plane | 
| draw-screen | Screen - windows and subwindows on a display | 
| drawmux | drawmux - multiplex stream of draw requests | 
| imagefile | imagefile: readgif, readjpg, readpicfile, readpng, readxbitmap, remap - processing external image file formats | 
| ir | ir - infrared remote control module | 
| mpeg | mpeg - interface to the mpeg device driver | 
| popup | Popup: mkbutton, changebutton, event, add - popup list box pseudo-widget | 
| prefab-0intro | Prefab: intro - Interactive TV tookit | 
| prefab-compound | prefab: Compound - windows for ITV toolkit | 
| prefab-element | prefab: Element - menu and display elements for ITV toolkit | 
| prefab-environ | prefab: Environ - environment for ITV toolkit to provide a graphics framework for a collection of items | 
| prefab-style | prefab: Style - fonts and colours for ITV toolkit | 
| print | Print - printing system | 
| pslib | pslib - postscript generation | 
| selectfile | selectfile - file browser | 
| tabs | tabs: mktabs, tabsctl - tabbed notebook pseudo-widget | 
| tk | Tk: toplevel, namechan, cmd, pointer, keyboard, imageget, imageput, quote - graphics toolkit | 
| tkclient | tkclient: makedrawcontext, toplevel, onscreen, startinput, wmctl, settitle, handler, snarfput, snarfget - window manager interface for Tk applications. | 
| volume | volume - volume control for an infrared interface | 
| wmclient | wmclient: makedrawcontext, window, snarfput, snarfget - window manager interface for Draw-based applications. | 
| wmlib | wmlib - low level access to window manager | 
| wmsrv | Wmsrv - core window-manager functionality and helper functions |