3.1. Desktop Client
Most apps are from F-Droid, we are just starting.
BBS-MUD Client: SyncTERM -> KildClient -> kbtin -> TinTin++
Bookmarks Manager: bookmarks.public -> bk_edit -> pmb -> b.
Browser: ungoogled-chromium -> Pale Moon -> GNU IceCat -> luakit / vimb / surf (tabbed) / Uzbl (tabbed) -> NetSurf (works in the framebuffer too) -> Arachne (works in the framebuffer too)
Browser (Command Line): w3m (can display images) -> Lynx -> Links2 (can display images) -> Netrik -> retawq
Browser (Gopher): GopherVR -> gopherfs -> UMN Gopher client -> sacc -> cgo -> Lynx
Chat Client: Finch (Pidgin) in irssi mode -> Centerim -> Bitlbee
E-Mail Archiver: Hypermail -> Lurker
E-Mail Client (MUA): Icedove/Thunderbird (+ Enigmail) -> Mailspring -> Emacs (Gnus) -> SquirrelMail -> Alpine -> Mutt -> mailutils ("mailx") -> S-nail ("mailx") + Muttprint
E-Mail Fetcher: Fetchmail -> fdm -> isync (mbsync)
E-Mail MIME: TNEF -> metamail
E-Mail SMTP Client: nullmailer -> msmtp -> esmtp -> SSMTP
IPTV: FreetuxTV -> iptvx
IRC Client: HexChat -> BitchX -> Weechat -> Irssi -> ii -> sic
Media Center: Plex -> Kodi ("XBMC", + Sonarr) -> Emby -> Popcorn Time -> LittleWeeb
Offline Reader: Kiwix -> Darcy Ripper -> HTTrack -> Stallman.js -> Wget
Online Radio: Nuvola Player
RSS Feed and Podcast: gPodder -> Raggle -> Liferea -> Newsbeuter (+ Podbeuter) -> Newsboat -> sfeed
Search Engine Scraper: Googler -> Surfraw (+ dmenu or slmenu)
Streams Catcher: Streamripper -> youtube-dl -> cclive -> youtube-pl -> RTMPDump -> quvi
UPnP (DLNA) Client: djmount
Usenet Client (Newsreader): Pan -> slrn ( + slrnpull + slrnface) -> Trn
VoIP Client: Empathy -> Jitsi -> Finch (Pidgin)
XMPP Client: Profanity
Booru: ahoviewer
Facebook: facy - > FBCMD (unmaintained) -> FBCLI -> Facebook CLI
Pastebin: pastebinit
Reddit: Reddit Comment Finder -> Cortex -> PRAW -> cReddit -> rtv
Telegram: Telegram Desktop -> ncTelegram -> telegram-cli -> Telegram-Purple
Youtube: mps-youtube -> youtube-viewer
Data Mining and Business Intelligence: JasperReports -> KNIME -> GNU Ferret -> GURGLE
Data Parsing: intltool -> XMLStarlet -> Flat file extractor (ffe)
Database (Datalog): Datalog Educational System, Datalog
Database (Middleware): MySQL Workbench -> Virtuoso Universal Server -> Orbada -> Autotable
Database (NoSQL): GZigZag, RRDtool, Dgraph, Redis, GNU Recutils
Database (SQL): MySQL -> Percona -> MariaDB -> CUBRID -> Ingres II -> ShellSQL
Enterprise Resource Planning (ERP): IDempiere -> LedgerSMB -> SQL-Ledger
Financial Markets Monitoring: JStock -> QtTrader -> Qtstalker
Full-Text Search: Xapian -> Tokyo Dystopia -> Groonga
Human Resource Management: OrangeHRM
Invoicing: Simple Invoices
Project Management: GanttProject
Backbone Framework: GNUnet -> OSF DCE (Distributed Computing Environment)
Chat: Tox -> Matrix (Matrix-Ircd, Riot) -> GNU Jami -> eircd -> P2PIRC -> nircd
Digital Library: Aletheia
Distributed File Systems: Samba -> NFS (nfs-utils) -> davfs2 -> Upspin -> IPFS
Distributed File Systems (Samba): SMB for FUSE (FuseSmb) -> SMBNetFS -> CIFS (cifs-utils)
E-Commerce: OpenBazaar + FIX Agora + Bitnation + GNU Taler
E-Commerce (Bitcoin): Qt Bitcoin Trader (Bitcoin Trader), Abe (Block Chain Browser)
E-Commerce (Bitcoin Wallet): Armory -> Bitcoin Core -> Monero
E-Mail: Notbit (Bitmessage)
Forum: Decentraland -> GNU Social (Pleroma, Mastodon) -> Syndie -> NNTPChan
Gossip Network (Network Service Discovery): peernet
Media Hosting: MediaGoblin -> Alexandria (not ready yet but this how it works) -> ipfs.pics
Mesh Network: Tinc -> cjdns -> BMX6 -> open80211s (802.11s) -> B.A.T.M.A.N.
Monetary Incentives: Storj + Gridcoin + Stream Token
Network Block Device: Usbredir -> nbd
Search Engine: searx -> Seeks -> YaCy (truly decentralized, would be wonderful if searx/seeks could feed its data to YaCy)
Search Engine (Gopher): Jugtail
Search Engine (Torrents): Magnetissimo -> magnetico
Streaming: Butter Project -> Livepeer -> PeerTube
Version Control (Decentralized Github): git-annex (+ git-annex assistant) -> GitTorrent
VPN: n2n -> PeerVPN
Wiki: ikiwiki
Containers: sandbox -> fakechroot -> FakeRoot -> PRoot -> chroot -> containerd -> OpenVZ -> User-mode Linux (UML) -> LXC -> Linux-VServer -> containers
Emulators: Systemd/Linux: systemd-shim, Windows: Wine (+ Wine Staging), Android: Anbox, OS X: Darling, Atari: Hatari (16/32-bit) and Atari800 (8-bit), CP/M: cpm (+ cpmtool), Spectrum: FBZX, Commodore: VICE, DOS: DOSBox
Hypervisors: Xen -> NOVA -> KVM
Network Virtualization: GNS3 -> nsnam
Video Game Console Emulation (ATARI): Stella
Video Game Console Emulation (XBOX): XQEMU
Video Game Console Emulation (MULTIPLE): Higan -> Mednafen -> RetroArch -> MAME -> AdvanceMAME (framebuffer support)
Video Game Console Emulation (NINTENDO): FCEUX/Citra, DeSmuME (Nintendo DS), Mupen64Plus (Nintendo 64), Dolphin (GameCube and Wii)
Video Game Console Emulation (SCUMM): ScummVM
Video Game Console Emulation (SEGA): Gens/GS, Exodus, Yabause (Sega Saturn), Lxdream, Reicast (Dreamcast)
Video Game Console Emulation (PLAYSTATION): PPSSPP, RPCS3, PCSX2
Virtual Assembler: GNUSim8085, spim
Virtual Machine: VirtualBox -> AQEMU + kvm -> Qemu + kvm -> Bochs
Virtual Machine (IBM Mainframes): Hercules
Virtual Machine (DEC): SIMH
Batch Renamer: Metamorphose -> GPRename -> vidir -> qmv (renameutils) -> mmv
Duplicate Files Removal: dupeGuru -> FSlint -> freedup -> fdmf -> dupmerge -> duff -> Fdupes -> jdupes -> rmlint
File Archiver: PeaZip -> Xarchiver -> Patool -> dtrx -> Atool -> dar -> tar -> pax
File Compression: arj, Zstandard (Zstd), Zip, lzop, Plzip, pxz, ECM (Error Code Modeler), p7zip, lbzip2, lrzip, pigz
File Conversion: nrg2iso, dmg2iso (dmg to iso), mdf2iso (mdf to iso), daa2iso (daa to iso), UIF2ISO (uif to iso), ccd2iso (img to iso), bin2iso (bin-cue to iso), bchunk (bin-cue to iso), mpq-tools (MPQ or MoPaQ), Macutils
File De-Compression Only: unace, cabextract, unrar, Lunzip, UnZip
File Manager: PCManFM -> Xfe -> SpaceFM -> File System Visualizer ("It's a Unix system, I know this!") -> Endeavour Mark II -> donnatella -> worker (+ imagemagick) -> Moxfm -> Emacs (Dired Plus Mode, Sunrise Commander, ranger.el, Image-Dired, ThumbsMode) -> Ranger -> Midnight Commander -> vifm -> FDclone -> Ytree -> rover -> CLEX -> nnn -> tree
File Search: Beagle -> Puggle -> ANGRYsearch -> Tracker -> DocFetcher -> regain -> lightmediascanner -> find
File Synchronization: Unison -> duplicity -> synk -> Rsync
Pictures Organizer: hydrus network -> Shotwell -> GTKRawGallery -> digiKam -> gThumb (+ gphoto) -> Mapivi -> BASH-Booru
RegEx Builder: regexxer -> Visual REGEXP -> txt2regex
Download Manager: JDownloader -> giFT (+ giFTcurs) -> aria2 -> cURL -> Wget -> snarf -> Axel
File Scraper: Grive2 (Google Drive) -> megatools (Mega) -> Rclone -> Plowshare
FTP Client: FileZilla -> lftp -> NcFTP
LAN Sharing: NitroShare -> Dukto
Media Miner: FlexGet -> Sonarr
Soulseek: Nicotine Plus -> Museek (mucous)
Torrent Client: qBittorrent -> RTorrent -> transmission-daemon (web interface by default, other frontends optional) -> CTorrent -> btpd + mktorrent
Usenet (File Grabber): LottaNZB -> SABnzbd -> NZBGet -> nzb -> nzbperl
x-y-zmodem: lrzsz
Application Profiling: CGprof -> Valgrind (+ Callgrind)
Browser Debugger: Firebug
Debugger: DDD -> CGDB -> OpenOCD -> GDB
Delta Encoding: xdelta -> Bsdiff
Forensic Analysis Framework: The Sleuth Kit -> DFF -> Radare
Java Profiling: VisualVM -> Quilt
Memory Scanner (Cheat Engine): scanmem & Gameconqueror -> varedit
Sandbox: Cuckoo Sandbox
Steganalysis: Virtual Steganographic Laboratory -> Stegdetect
Cameras: ZoneMinder (CCTV), Motion (motion detection), gPhoto (connecting digital cameras), ccdciel
Car (as in automobile): can-utils
CD-DVD Burn and Copy (Backends): cdrtools -> cdrkit -> cdrskin
CD-DVD Burn and Copy (Frontends): K3b -> Brasero -> dvd+rw-tools -> xorriso -> cdw
CD-DVD Cue Files: cuetools -> cuecmd
CD-DVD Information: cd-discid -> cdstatus
CD-DVD Ripping: Sound Juicer -> fre ac -> cdparanoia (+ ABCDE)
Data Recovery: fatcat -> ext3grep -> giis (gET iT i sAY) -> extundelete -> Magic Rescue -> dvdisaster -> TestDisk (PhotoRec) -> ddrescue
Device Management (and module autoloader): evdev -> udev -> vdev
Disk Cloning and Writing: devio -> dd -> dcfldd -> dc3dd
Display Color Temperature: Redshift -> sct -> luminous
Display Settings: xrandr -> DDCcontrol -> fbset
Displays (Miracast): MiracleCast
Hardware Bus: multipath-tools, I2C Tools (i2c-tools), IPMI Tool (ipmitool, ipmiutil) (IPMI DANGEROUS IF ENABLED)
Hardware RAID: mdadm -> dmraid
Hibernation: TuxOnIce -> uswsusp -> pm-utils -> shutdownasap -> watchdog
Home Automation: LinuxMCE
Keyboard Bindings: Xbindkeys -> sxhkd -> bind (readline) -> loadkeys (+ keymaps)
Keyboard Input Language: iBus -> SCIM -> Fcitx -> uim (+ Anthy)
Keyboard Layout: XKB -> xmodmap -> KBD
Media Transfer Protocol (MTP): MTPfs -> jmtpfs -> simple-mtpfs
Microcontrollers: AVRDUDE
Mounting: AcetoneISO -> Udisks (+ udevil) -> Lightweight Device Mounter (ldm) -> USBmount -> pmount -> bashmount -> mount (.ISO files too) -> udev rules
Mouse: xbanish -> keynav -> GPM
Power Management: tpfancontrol -> tpacpi-bat -> thinkfan -> TLP -> PowerTOP -> Powertweak
Printers: CUPS -> LPR
Scanners: Scanner Access Now Easy (SANE)
Telescope: Talon
Tv (DVR): xawtv -> tvtime
Tv (Multicast): udpxy -> IGMPproxy
Undevolting and Power Saving: TurionPowerControl -> Linux-PHC -> cpufrequtils -> cpupower -> schedtool
UPS: egctl -> Network UPS Tools (NUT) -> apcupsd
Drive Profiling: Smartmontools -> fio -> sdparm -> hdparm
General Benchmarking: collectd -> Phoronix Test Suite -> HPC Challenge Benchmark (hpcc) -> mcelog -> ProcBench -> Sysbench
Network Data Visualization: weathermap4rrd (rrd) -> Xtract (pcap)
Server Benchmark: Siege
Sort Benchmark: gensort
System Tracing: SystemTap -> LTTng -> OProfile -> Sysdig -> dtrace -> strace -> trace-cmd (ftrace) -> perf + FlameGraph
General Information: zCI -> inxi
Hardware Information: vdpauinfo -> lshw -> hwloc -> lsscsi -> edac-utils -> usbutils (lsusb) -> pciutils (lspci) -> util-linux (lsblk, blkid, dmesg) -> acpitool dmidecode
Screenshot Information (Bash): Neofetch -> screenFetch -> envee
Screenshot Information (C): Linux_Logo
Screenshot Information (Perl): screenfo -> alsi
Software Information: vrms -> file -> ldd -> lsb_release -> os-prober -> uname (GNU Coreutils)
Database Monitoring: Mytop
Disk Usage: QDirStat -> Baobab -> xdiskusage -> XDU -> dfc -> Ncdu -> ls++ -> tdu -> ncdt -> du + df (GNU coreutils)
Geolocation: Prey
Hardware Monitoring: lm-sensors (psensor for a GUI) -> CrazyDiskInfo -> Hddtemp
Log Visualizer: glTail -> Logstalgia -> ccze
Network Monitoring: IPTraf -> tcptrack -> IPTState -> NetHogs -> iftop, dnstop
Port Monitoring: psad
System Latency: LatencyTOP
System Monitor: gnome-system-monitor -> psDooM -> HardInfo -> GKrellM -> treeps -> Conky -> xosview -> Glances -> dstat -> atop -> htop -> nmon -> procinfo -> Sysstat (sar, mpstat, pidstat, iostat, sadf) -> procps (ps, free, vmstat, top, pmap, nice)
Web State Monitor: Nagios (+ NagVis) -> Sysmond -> sysmon
Wi-Fi Network Monitor: wavemon
ANSI Drawing: MysticDraw -> SHPaint
ANSi Viewer: ANSiMat
ASCii Animation: blessed -> Durdraw -> drawille
ASCii Banner: shellpic -> TOIlet -> FIGlet -> sysvbanner
ASCii Drawing: JavE -> Aewan -> cadubi -> CAVE WALL -> textdraw
ASCii Presentations: wopr -> blessed-contrib
Image to ASCii: jp2a
Video to ASCii: libcaca -> AAlib
Audio Effect Plugins: awesfx (SoundFont), Vamp, zam-plugins (LADSPA/LV2/VST/JACK), LV2 (x42-plugins), LADSPA (tap-plugins), DSSI (dssi-utils, dssi-vst), ALSA plugins (alsa-plugins)
Background Sound: GNU GTick -> Ambient Noise -> ctronome
Digital Audio Workstation: Rosegarden -> Ardour -> LMMS
DJing: Mixxx
Ear Training: LenMus -> GNU Solfege
Multiple Audio Streams: pulseaudio -> apulse -> ALSA (aloop, Softvol, Dmix)
Music Player: Audacious (+ Winamp Classic skin + GJay) -> Clementine -> Open Cubic Player -> MPD (vimus/ncmpcpp) -> cmus -> mp3blaster (runs with "aoss mp3blaster" or compiled with ALSA) -> MikMod -> MOC (+ moc-ffmpeg-plugin, dmenu_mocp) -> simple audio daemon (sad)
Music Visualization: Spectrum3d -> Le Biniou -> projectM -> cava -> cli-visualizer
Scorewriter: MuseScore -> LilyPond -> eTktab -> Emacs (lyqi) -> Philip's Music Writer (pmw) -> ABCmidi (abcpp + abc2prt + abcm2ps)
Software Sampler: LinuxSampler -> orDrumbox -> Hydrogen
Synthesizer: AlsaModularSynth -> ZynAddSubFX -> FluidSynth (+ SoundFonts)
System Sound Compatibility: WineASIO, oss2jack, oss-compat, alsa-oss
System Sound Extensions: pulseaudio -> Jack (jack, jack-audio-connection-kit) -> ESound (esound-common)
System Sound Utilities: pavucontrol (pulseaudio) -> JACK Rack (for Jack) -> JAMin (for Jack) -> Qastools -> gnome-alsamixer -> aumix -> Rexima -> ALSA tools (alsa-tools, alsa-tools-gui) -> Alsaequal -> alsa-utils (alsamixer, amixer, aplay, arecord)
Tonal Feature Analysis: CLAM Chordata -> Sonic-> Spek -> Pause
Tracker Editors: MilkyTracker -> Schism
Trackers: SID-Wizard -> GoatTracker
Tray Icon: Volume Icon -> Volti
Bitmaps to Vector Conversion: AutoTrace -> Potrace
Diagram Editor: Pencil Project -> Dia -> Graphviz
Digital Drawing (Bitmap Graphics): Krita -> MyPaint -> Xournal -> XPaint -> GrafX2 / uberpaint
Digital Drawing (Coloring): OpenColorIO -> deepcolor -> STYLE2PAINTS
Digital Drawing (Fonts): FontForge
Digital Drawing (Vector): Inkscape -> Xfig -> gozer -> ImageMagick
Fonts Conversion: bdftopcf, PSF Tools, pcf2bdf, otf2bdf, bdf2psf
Fractals and Random Computer Artwork: Mandelbulber -> Fyre -> Wassily
Image Editing: RawTherapee -> darktable -> Gimp -> Netpbm -> G'MIC -> GraphicsMagick -> ImageMagick (display, import) -> Gifsicle
Image Optimizing: OptiPNG -> pngcrush -> pngquant
Image Viewer: Feh -> sxiv -> zgv -> lsix -> sdump -> display (ImageMagick) -> fim / fbi (fbida) -> idump
Plotting: Gnuplot -> Ngraph-gtk -> ygraph -> PLplot -> FRTPLOT -> Picviz
Screenshots: Shutter -> scrot -> maim -> shot.sh -> import (ImageMagick) -> fbcat (FBGrab)
Datamoshing: Autodatamosh
Digital Animation (3D): Blender
Flash Player: Lightspark -> Gnash
HDR (High-Dynamic-Range): pfstools
Screencasting: Open Broadcaster Studio -> SimpleScreenRecorder -> XVidCap -> glc -> FFmpeg -> ttyrec (+ seq2gif)
Video Editing: Kdenlive -> Avidemux -> OpenShot -> Cinelerra-cv -> Melt -> AvxSynth -> blind -> FFmpeg
Video Effects Plugins: Frei0r
Video Player: nvlc (VLC) -> MPV -> MPlayer -> fbff -> ffplay
Video to gif: Video2Gif -> QGifer -> convert (ImageMagick) -> FFmpeg
Video Transcoding: HandBrake -> WinFF -> FFmpeg / avconv
Bandwidth Saver: Wondershaper
Bandwidth Testing: speedtest-cli -> speed-test
Bluetooth: btmgmt -> Bluez-tools
DHCP Client: dhclient -> dhcpcd
DNS Encryption: DNSSEC, DNSCrypt
DNS Resolution: dnsmasq -> Unbound + NDS -> BIND9 -> djbdns
MAC Manipulation: GNU MAC Changer (macchanger)
Network Encryption: OpenSSL -> LibreSSL -> GnuTLS -> IPsec / SAE (802.11s)
Network Manager: Wicd -> NetworkManager -> ConnMan -> SetNet
Networking Tools: WvDial -> ethtool -> iproute2 (ip, ss) -> net-tools (ifconfig, netstat)
Point-to-Point Protocol: Point-to-Point Protocol daemon
Wireless Tools: rfkill, iw -> Wireless Tools for Linux, iwd -> wpa_supplicant
Address book: abook
Desktop Publishing: Scribus
Document Format Conversion: unoconv -> Pandoc -> Yodl -> GNU a2ps -> inf2manp
Document Processor: Emacs (AUCTeX) -> LyX -> GNU TeXmacs
Ebook Utilities: DeDRM_tools
Ebook Utilities (CHM): xCHM -> CHMLib (extract_chmLib)
Ebook Utilities (Epub): Ebook Tools (ebook-tools)
Ebook Utilities (PDF): PDF SaM -> Poppler -> PDFtk
Ebook Utilities (PostScript): PSUtils -> ghostscript
Ebook Viewer: Calibre -> Okular -> Zathura -> JFBView / fimgs (fim) / fbgs (fbida) / fbpdf
Flashcards: awk flashcards -> Anki
Gamification: HabitRPG -> Habitica
Mind Mapping: FreeMind
Office Suites: LibreOffice -> Siag Office -> catdoc (xls2csv, catppt, wordview)
Outliner: TreeSheets -> Vault 3 -> GJots2 -> TuDu -> Emacs (Org-mode) -> Vim (Vimoutliner or Vim-orgmode) -> hnb -> snb
Personal Accounting: GnuCash -> Ledger -> GNU Pem
Personal Organizer: Task Coach -> Wyrd -> wtf -> Taskwarrior -> calcurse -> todo.txt-cli -> when -> cal
Presentation: Beamer -> Sozi -> Text Presentation Program
Repetitive Strain Injury: Workrave
Speed Reading: Flinks -> WordFlashReader -> GnomeRSVP -> spread0r -> speedread
Spell Check: Ispell -> Aspell
Spreadsheets: Libreoffice Calc -> Gnumeric -> Oleo -> SC-IM
Text Editor: Vim -> Nano -> Neovim -> Kakoune -> vile -> mg -> GNU Zile (minimalist Emacs clone) -> nvi -> Elvis (minimalist Vi clone) -> ed
Text Editor (IDE): Atom -> NetBeans -> Code Blocks -> Emacs (nox) -> Vim -> xwpe (full IDE in the terminal)
Text Encoding: fuse-convmvfs, Dos2Unix, ASCII
Text Formatting and Pretty Printing: par -> fmt (Textutils) -> MSORT
Text-To-Speech: Orca -> Gespeaker -> eBook-speaker (+ pandoc) -> eSpeak
Typesetting: LaTeX -> Texinfo + Pinfo -> Discount (Markdown) -> AFT -> groff (tbl, pic, eqn, chem, music, dpic, grohtml)
Typing Training: Klavaro -> nlkt -> GNU Typist
Word Processor: LibreOffice Writer -> Abiword -> MinEd -> WordGrinder
CD/USB (Custom Installer): Respin -> Remastersys -> Distroshare -> PinguyBuilder -> Customizer -> Ubuntu Customization Kit -> Mklivecd
CD/USB (Live): UNetbootin -> MultiCD
Gaming Platform: LGOGDownloader (GOG.com), SteamCMD (Steam), Lutris, Gelide
Language Specific: bpkg (Bash scripts) -> CPAN (+ Pinto) (Perl) -> clib (C)
Package Creation: OBS (Open Build Service) -> src2pkg -> CheckInstall -> GNU Stow -> lt
Portable Apps: Flatpak -> Snappy -> AppImage
System Backup: Systemback -> Bacula -> FSArchiver -> CYA
Universal Package Managers: Alien -> LinuxBrew -> pkgsrc -> GNU Guix
Distros: Security Scenario Generator (SecGen) -> Damn Vulnerable Linux -> Metasploitable -> Kioptrix
Web Apps: Mutillidae -> hackxor -> WebGoat
Bluetooth: btscanner -> bluesniff
DNS Client: whois, dnsenum, dnstracer, slookup, bind-tools (nslookup, host, dig)
Link Scanner: Metagoofil -> LinkChecker -> Linklint (+ linklint2dot)
Network Mapping: Open Visual Traceroute -> EtherApe -> Paris Traceroute -> Dublin Traceroute -> MTR -> Layer Four Traceroute (LFT) -> tcptraceroute -> iputils (Ping, traceroute, tracepath, arping) -> ipcalc -> GeoIP
Packet Sniffer: Tshark (Wireshark TUI) -> tcpflow -> tcpdump + tcpick
Reconnaissance Framework: Recon-ng -> DMitry -> dsniff (urlsnarf, filesnarf, webspy, Tcpkill, macof, arpspoof) -> Nmap -> ngrep
General: netcat -> ncat (nmap) -> cryptcat (Netcat) -> socat -> Netsed
Man-in-the-middle Attack: sslstrip -> Morpheus -> evilginx2 -> bettercap -> Ettercap
Traffic Generator: Mausezahn
Traffic Replay: Tcpreplay
BIOS: CmosPwd
Compressed Files: RarCrack
General: John the Ripper / Hashcat
PDF: pdfcrack
Remote: THC Hydra
WiFi: Reaver -> Aircrack-ng
Windows: Ophcrack
Backdooring: Veil -> Cymothoa -> Backdoor Factory -> Evilgrade -> EvilAbigail
Cross-Scripting: xsser
Exploit Famework: Metasploit -> Metasploit (Perl), WebSploit -> w3af
Post Exploitation: Empire -> Post Exploitation Collection (Windows) -> mimikatz (Windows) -> Post Exploitation Linux Toolkit -> poet
SIP: Sippts
Social Engineering: SET (Social Engineering Toolkit), BeEF (The Browser Exploitation Framework Project)
SQL Injection: sqlmap
SSH Denial: screwSSH
Web Application Vulnerability: Nikto
Windows Registry Editor: Offline NT Password & Registry Editor (chntpw)
Anti Stylometry: Anonymouth
Data Erasure: Dban -> bleachbit_cli (BleachBit) -> shred (GNU Coreutils)
Boot Encryption: cryptboot
Disk Encryption: dislocker -> cryptsetup (dm-crypt)
File Encryption: GNU Privacy Assistant -> MCrypt -> ccrypt -> GNU Privacy Guard
Filesystem Encryption: eCryptfs -> EncFS -> StegFS
Folder Encryption: VeraCrypt -> Tomb -> tcplay (full TrueCrypt implementation and still minimalist)
Encrypted Version Control: Keyringer
Identity Generator: The Random Identity Generator (rig)
Password Manager: KeePassX / KeePassXC -> pass (+ pass-tomb, + passmenu) -> kpcli
Password Sync: KeySync
Steganography: StegoShare -> Steghide -> SNOW (stegsnow) -> UUDeview -> Steganoroute
Build Automation: Ninja -> mk -> GNU make -> bmake -> Icmake -> Jam, Gnulib
Build Script Generation: Gradle -> Cmake (+ cmocka + ECM) -> Autotools (Automake, Autoconf + GNU Autoconf Archive, Libtool) -> mk-configure
Code Beautifier: TagSoup -> UniversalIndentGUI -> HTML Tidy -> tidyp -> Indent
Compilers (Assembly): NASM -> Yasm -> as (GNU binutils)
Compilers (C): clang -> Tiny C Compiler (tcc)
Compilers (Java): Java SE (JDK) -> IcedTea (OpenJDK) -> GraalVM (compile multiple languages into JVM) -> JamVM (JVM) -> FastJar (Compiler)
Compilers (Multiple languages): GCC (GNU -native- Compiler for Java, GnuCOBOL, GNU Fortran) + colorgcc
Cross-compiler: Buildroot -> Crosstool-NG -> dev86
Documentation Browser: Devhelp -> Zeal
Documentation Generator: perlpod, bashdoc, Doxygen, GNU help2man
Issue Tracking System: Bugzilla -> GNATS
Linting: ShellCheck, GNU Source-highlight
Memory Allocation: jemalloc -> boehm-gc
Parser Generators: ANTLR -> Ragel-> AutoGen -> GNU bison and Flex -> re2c + lemon -> GNU m4
Program Transformation: FermaT, Coccinelle, CIL, Stratego/XT
Random Hacks: patchelf, elfhacks, SWIG, Gengetopt
Source Code Count: Unified Code Count (UCC) -> CLOC
Source Code Navigation: GNU idutils, cflow (+ cflow2dot), LXR: The Linux Cross Referencer -> GNU GLOBAL -> cscope -> Ctags -> cgvg -> ack -> ag
System Query: sysconftool, Installwatch, pkgconf
Version Control: Git (+ tig) -> CVS (+ CVSGraph) -> Fossil -> tla (GNU Arch) -> RCS + mr + quilt
Configuration Management: Puppet -> LCFG -> CFEngine -> cdist
Control Panel: ZPanel -> Vesta Control Panel -> Webmin
Diskless Booting: iPXE -> netboot
PC-Mobile Connection: KDE Connect -> Wammu -> BitPim -> AndroidTools
Remote Desktop (Client): rdesktop -> Remmina -> fbvnc
Remote Desktop (Client and Server): X2Go
Remote Desktop (Server): xrdp
Remote File Manager: KodExplorer
Remote Login: Mosh -> OpenSSH -> lsh -> Dropbear
Remote X Apps: Xpra > X11 forwarding
Serial Console: Minicom -> Picocom -> Qodem -> GNU Screen
Server Provisioning: FAI
Wake-on-LAN: wakeonlan
Artificial Intelligence: Arcade Learning Environment, ETHNOS, Conscious Artificial Intelligence, OpenCog, OpenAI
Astronomy: Sky Chart (Cartes du Ciel) -> astroTools + evTools -> GNU Astronomy Utilities (Gnuastro)
Astronomy (Planetarium): Stellarium -> Celestia -> XEphem -> SkyCat
Astronomy (Satelline Tracking): SaVi satellite constellation visualizer
Bioinformatics: OpenSim, Cytoscape, BioJava -> UGENE -> EMBOSS -> SAMtools -> BioPerl
CAD: AutoCAD -> Blender -> FreeCAD -> LibreCAD -> OpenSCAD
Computational Fluid Dynamics: TELEMAC -> FEATFLOW -> OpenFOAM -> Gerris
Computer Algebra System: Singular -> Axiom -> Maxima (+ PLplot) -> bc + GNU Units
Geography (Geographic Information System): qGIS -> FWTools (OGDI, PROJ.4, GDAL/OGR, MapServer, OpenEV)
Geography (Subway Map): qMetro
Geography (Virtual Globe): Marble
Graphing Calculator: GraphMonkey -> Lybniz -> KAlgebra -> TilEm
Multi-Agent (MA) Simulation: Mobility Testbed -> Galatea -> NetLogo -> Golly (Conway's Game of Life clone)
Physics Simulation: OpenModelica -> CalculiX -> Elmer -> MCSim
Semiconductor Modeling (TCAD): GNU Archimedes (and GNU Nano-Archimedes)
Statistical Package: SageMath -> Physics Analysis WorkStation -> ROOT -> gretl -> PSPP (+ PSPP-Perl)
Weather Forecast: XTide -> AWeather -> My Weather Indicator -> wego -> Weather Util -> rrdweather -> curl wttr.in/YOURCITY, YOURCOUNTRY
Access Control (Kernel Patches): grsecurity + gradm -> Linux Intrusion Detection System -> SecurelLevel -> PaX -> RSBAC
Access Control (Linux Security Modules (LSM)): SELinux -> TOMOYO Linux -> Smack -> AppArmor
Authentication: Polkit -> ConsoleKit -> Sudo (visudo) -> Linux PAM -> checkpassword -> shadow
Extended File Attributes: EVM -> IMA -> inotify
Resource Usage Control: cpulimit -> ulimit (Bash) -> Disk Quota -> quotatool
Sandbox: Arkose -> Firejail -> nsjail -> Bubblewrap
Client: HoneyC -> Capture-HPC
Distro Bundle: HoneyDrive -> ADHD
Web-Based: HIHAT
Anti Backdoor: rosenbridge, me_cleaner
Anti Malware: ClamTk -> ClamAV -> Linux Malware Detect (LMD)
Host System Auditing: Bastille -> OpenVAS -> Linux Security Auditing Tool (LSAT) -> Lynis
Integrity Check: PaX Utilities -> AIDE -> systraq -> Tripwire -> Samhain
Rootkit Detection: rkhunter, Chkrootkit, Unhide
System Logging: socklog (runit) -> Rsyslog -> Syslog-ng -> sysklogd
Deep Packet Inspection (DPI) Block (Layer 7 Firewall): ipp2p -> l7-filter -> OpenDPI
Deep Packet Inspection (DPI) Circumvention: zapret
Firewall: ufw (Uncomplicated Firewall) + gufw (GUI) -> arptables -> ebtables -> iptables (+ ipset) -> nftables + conntrack-tools
Man-In-The-Middle (MITM) Detection: arpwatch -> ArpON -> Arpalert
Network Intrusion Detection: Snort -> Suricata
Network Intrusion Prevention: Fail2ban -> Sshguard
Network Logging: CoCaLoRes -> ulogd
BBS Server: Citadel -> Synchronet -> Mystic BBS -> BBS100
Bitcoin Miner: BFGMiner
Blog: finger / cfingerd
Bluetooth: BlueALSA
Captcha: cool-php-captcha
Chat: sshtalk -> util-linux (write, wall, mesg)
Cloud File Server: Google Drive -> Nextcloud -> Syncthing -> sftp / SSHFS (SSH)
CMS: WordPress -> GetSimple CMS -> werc
Collaborative Real-Time Editor: Gobby -> EtherCalc -> Cryptpad
Direct Connect Server: uhub
DLNA: Universal Media Server -> ReadyMedia (a.k.a. MiniDLNA) -> MiniUPnP
DNS Spam Detector: DNS Flood Detector
Document Management System: OpenKM -> LogicalDOC -> EPrints
Dynamic DNS (DDNS): DDClient
E-Mail Filtering (LDA): Dovecot -> procmail
E-Mail Indexing: Archmbox -> Chewmail -> Notmuch -> mairix
E-Mail Mailing Lists: Mailman -> Sympa -> Dada Mail -> ezmlm -> mlmmj
E-Mail Notifier: mswatch
E-Mail Server (MTA): Mail-in-a-Box -> Kolab -> Sendmail -> Postfix -> Exim -> cmail -> qpsmtpd -> OpenSMTPD -> qmail
E-Mail Spam Filter: Bogofilter -> DSPAM -> SpamAssassin -> SpamProbe + Hashcash + rbldnsd
File Distribution: zsync
Forum: lainchan -> vichan -> Akari-BBS -> sshchan -> KrautBBS -> 1436chan
FTP Server: CurlFtpFS -> vsftpd
Gopher Server: Gophernicus -> Bucktooth (Gopher) + Bucky (for HTTP exit)
Groupware: Collabtive -> Alfresco -> eXo Platform -> Citadel/UX
Image Hosting: img.bi -> Up1
IRC Bouncer (BNC): ZNC -> bip
IRC Fileserver: iroffer
IRC Server: UnrealIRCd -> Charybdis -> InspIRCd -> ngIRCd
Learning Management System: GnuTutor -> OpenExpert -> Syllog
MUD Server: LambdaMOO -> PennMUSH
Pastebin: Stikked -> Paste -> PrivateBin
Proxy Server: Tinyproxy
Service Manager: xinetd -> linetd -> inetd (GNU inetutils) -> knockd -> TCP Wrappers (tcpd, tcpdchk) -> ucspi-tcp
Streaming: Syncplay -> Peerflix (+ Torrentflix) -> Libresonic -> Icecast (+ DarkIce -> ezstream -> oggfwd) -> trx: Realtime audio over IP -> SRS -> VLC -> FFmpeg
Tunneling: HTTPTunnel -> VTun -> ProxyChains -> VPNEncap -> VPNCHAINS
Web Filtering: Ad blocker on a web browser -> Pi-hole -> DansGuardian -> Privoxy -> Hostsblock
Web Server: Apache -> Nginx -> lighttpd -> Hiawatha -> Monkey -> GNU MyServer -> webfs -> darkhttpd -> Bucky (Bucktooth HTTP exit)
Web Server Certificate: Dehydrated -> acmetool
Wireless Access Point: hostapd
Domain Specific Authentication Server: Ident (IRC), SKS (PGP)
RADIUS: FreeRADIUS -> GNU Radius
SSO: krb5 (Kerberos) + keyutils -> GNU Shishi (Kerberos)
BIOS: efibootmgr -> SeaBIOS -> Coreboot -> Libreboot
Boot Loader: GRUB 2 -> GRUB Legacy -> SYSLINUX (+ Hardware Detection Tool -HDT-) -> LILO (or ELILO for UEFI) -> AiR-Boot -> Das U-Boot (u-boot-tools)
Boot Loaders (load on running machine): loadlin -> Kexec (kexec-tools)
Cache: Memcached, EnhanceIO -> dm-cache -> bcache
Core Utilities: moreutils -> Mtools -> util-linux -> GNU Coreutils -> BusyBox -> Asmutils and ARMutils
Custom Initramfs: mkinitcpio -> dracut -> Genkernel -> mkinitramfs -> umkinitramfs
Filesystem: CP/M (cpmtools), HFS Utilities, SquashFS (squashfs-tools), fuseflt, UnionFS (unionfs-fuse), udftools (UDF), F2FS (f2fs-tools), exFAT (exfat-utils, fuse-exfat), FAT (dosfstools), Btrfs (btrfs-progs), XFS (xfsprogs, xfsdump), Ext4, JFS, Reiser4, Bcachefs
IPC: DBus -> ubus -> RPCBind -> ipcs (util-linux)
Kernel Modules: NDISwrapper -> ibm-acpi-> kmod (lsmod, insmod, modprobe)
Kernel Patches: V86 mode support, GoboHide, Kernel_gcc_patch, Linux-ck, Liquorix, Linux-rt, GNU Linux-libre, Linux Tiny
Kernels: LUnix, Linux + Lux (kernel updater), GNU Mach, RTLinux, Muen, HiStar
Logical Volume Management: LVM2
Multiplexer Wrappers: ucspi-unix, ucspi-ipc, socket_wrapper, nss_wrapper, uid_wrapper, resolv_wrapper, pam_wrapper
Network Time Protocol: clockspeed -> Network Time Protocol daemon (ntpd) -> chrony -> OpenNTPD
OS Frameworks: OpenStack -> Genode
Partitioning: Gparted -> GNU Parted -> util-linux (cfdisk, fdisk, sfdisk, mkfs, mkswap, swapon, swapoff)
Partitioning Fixes: u3_tool, ms-sys
Settings Manager: Youker Assistant -> Linux Lite Control Center -> Elektra -> Augeas -> Climate -> The Fuck -> Suicide Linux
Virtual Filesystem: FuseIso -> Autofs -> AVFS -> afuse -> bindfs
Service Manager: OpenRC (includes an optional own init) -> runit (includes an optional own init) -> Ignite -> daemontools-encore -> perp
Startup Scripts Manager: bum -> svsh -> sysv-rc-conf -> chkconfig
Event: incron -> inotify-tools -> entr -> wendy -> ACPI event daemon (acpid) -> waitfordevice (w4d)
Queue: Slurm -> Task Spooler
Time: Anacron -> fcron -> bcron -> dcron -> at
Application Launcher: ratmenu -> xcmd -> dmenu -> nenu
Boot Screen: Plymouth -> Splashy -> Fbsplash -> <BOOTLOADERS>
Compositing Window Manager: Compiz -> Compton -> Xcompmgr
Desktop Animated Character: Kawari + Ninix-aya (for Ukagaka) -> Gnome KiSS -> Oneko -> xevilteddy -> Xteddy
Desktop Automation: Autokey -> Sikuli -> Easystroke -> xdotool -> GNU Xnee
Font Settings: xfontsel + mkfontdir -> fontconfig -> /etc/X11/xorg.conf
Graphics Settings: RiceDB -> Wpgtk -> LxAppearance -> dconf -> Xset -> /etc/X11/xorg.conf
Login Manager: SLiM -> Qingy
Nested Display: Xephyr -> Xnest
Notification (Daemon): dunst -> slstatus -> SiND (Simple Notification Daemon)
Notification (Server): Libcanberra + Libnotify -> xmessage
Panel: Avant Window Navigator -> Global Menu -> Tint2
Screensaver: XScreenSaver -> XLockmore -> i3lock -> sxlock -> slock -> xset
Status Bar (Client): Dzen -> bevelbar -> Lemonbar
Status Bar (Server): monky -> i3status
Wallpaper Changer (Animated): Xphoon, xfireworks, Xsnow, xmountains, Xplanet, ImageMagick (animate)
Wallpaper Changer (Still): FEH -> xsetroot -> hsetroot -> imagemagick (but using 10MB more RAM than the others)
Wallpaper Changer (Terminal As Wallpaper): xli -> root-tail -> xrootconsole
Wallpaper Changer (Video): VLC (nvlc) -> mpv -> MPlayer
Window Manager: FVWM (+ FvwmTabs and 4dwm theme) -> IceWM (Windows XP-like) -> i3 -> Amiwm (Amiga-like) -> mlvwm (Macintosh-Like) -> MWM -> Ratpoison -> dwm (+ dwmstatus) -> FrankenWM -> TinyWM -> s3d (+ s3dfm, it's a 3D desktop independent of X!) -> Twin (independent of X) -> VWM (independent of X)
Window Manipulation: QuickTile -> wmctrl -> wmutils
Worskpace Pager: 3D-Desktop -> Skippy-XD
X Event Display: xprop -> xwininfo -> xev