network

netcat : NC(1) BSD General Commands Manual NC(1) nc — arbitrary TCP and UDP connections and listens
ping : 6 send ICMP ECHO_REQUEST to network hosts
nmcli : – commandline tool for controlling NetworkManager
telnet : user interface to the TELNET protocol
openssl : OpenSSL command line tool
sftp : secure file transfer program
...

shell

gnome-terminal : is a terminal emulation application.
busybox : The Swiss Army Knife of Embedded Linux
usermod : modify a user account
which : locate a command
fusermount : mount and unmount FUSE filesystems
watch : execute a program periodically, showing output fullscreen
...

filesystem

resize2fs : ext2/ext3/ext4 file system resizer
chown : change file owner and group
fsck : check and repair a Linux filesystem
passwd : change user password
hdparm : get/set SATA/IDE device parameters
mkfs.ext3 : create an ext2/ext3/ext4 filesystem
...

programming

strace : trace system calls and signals
startpar : start runlevel scripts in parallel
MAKEDEV : create devices
busybox : The Swiss Army Knife of Embedded Linux
kmk_sed : framework for writing simple makefiles for complex tasks
setkeycodes : load kernel scancode-to-keycode mapping table entries
...

file

egrep : , fgrep, rgrep print lines matching a pattern
hexdump : , hd ASCII, decimal, hexadecimal, octal dump
passwd : change user password
su : change user ID or become superuser
mkfs.ext2 : create an ext2/ext3/ext4 filesystem
ping : 6 send ICMP ECHO_REQUEST to network hosts
...

graphic manipulation

start-stop-daemon : start and stop system daemon programs
gimp : an image manipulation and paint program.
mkntfs : create an NTFS file system
dvipos : compute positions in a DVI file
grap2graph : convert a grap diagram into a cropped bitmap image
rmsgmerge : Extract translatable string from given input ruby script files.
...

database

mysqlimport : a data import program
mysqld_safe : MySQL server startup script
update-grub : stub for grub-mkconfig
time : run programs and summarize system resource usage
avconv : avconv video converter
getconf : Query system configuration variables
...

X

gnome-terminal : is a terminal emulation application.
xfreerdp : FreeRDP X11 client
zenity : display GTK+ dialogs
update-grub : stub for grub-mkconfig
yuvdenoise : Motion-Compensating-YUV4MPEG2-frame-denoiser
avconv : avconv video converter
...

package management

dpkg-reconfigure : reconfigure an already installed package
apt-config : APT Configuration Query program
passwd : change user password
cweave : translate CWEB to C and/or TeX
python2.7 : an interpreted, interactive, object-oriented programming language
dh_installdeb : install files into the DEBIAN directory
...

printer

ppdc : cups ppd compiler
ghostscript : Ghostscript (PostScript and PDF language interpreter and previewer)
sldtoppm : convert an AutoCAD slide file into a portable pixmap
lprm : cancel print jobs
sensible-pager : pager, sensible-browser - sensible editing, paging, and web browsing
cweave : translate CWEB to C and/or TeX
...

text manipulation

dvipdf : Convert TeX DVI file to PDF using ghostscript and dvips
tac : concatenate and print files in reverse
iconv : Convert encoding of given files from one encoding to another
bluez-simple-service :
unwrapdiff : demangle word-wrapped patches
fmtutil-sys : utility for maintaining TeX format files system-wide
...

privacy

passwd : change user password
nohup : run a command immune to hangups, with output to a non-tty
tor-resolve : resolve a hostname to an IP address via tor
ping : 6 send ICMP ECHO_REQUEST to network hosts
cweave : translate CWEB to C and/or TeX
ssh-add : adds private key identities to the authentication agent
...

sound manipulation

gst-launch-1.0 : build and run a GStreamer pipeline
audacity : Graphical cross-platform audio editor
start-stop-daemon : start and stop system daemon programs
ogmsplit : Split OGG/OGM files into several smaller OGG/OGM files
sndfile-metadata-set : set metadata in a sound file
spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
...

Access Control List

su : change user ID or become superuser
pdb3.3 : the Python debugger
spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
groupadd : create a new group
ping : 6 send ICMP ECHO_REQUEST to network hosts
iconv : Convert encoding of given files from one encoding to another
...

file compression

update-grub : stub for grub-mkconfig
7zr : A file archiver with highest compression ratio
iconv : Convert encoding of given files from one encoding to another
ogmdemux : Extract streams from OGG/OGM files into separate files
znew : recompress .Z files to .gz files
passwd : change user password
...

boot settings

dh_installppp : install ppp ip-up and ip-down files
kerneloops : program to collect and submit kernel oopses to kerneloops.org
cweave : translate CWEB to C and/or TeX
grub-mkimage : make a bootable image of GRUB
passwd : change user password
spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
...

text editor

sha1sum : compute and check SHA1 message digest
view : Vi IMproved, a programmers text editor
bibtex.original : make a bibliography for (La)TeX
lame : create mp3 audio files
loadunimap : load the kernel unicode-to-font mapping table
find : search for files in a directory hierarchy
...

webserver

a2ensite : enable or disable an apache2 site / virtual host
passwd : change user password
iconv : Convert encoding of given files from one encoding to another
arping : send ARP REQUEST to a neighbour host
lame : create mp3 audio files
loadunimap : load the kernel unicode-to-font mapping table
...

font

spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
debugfs : ext2/ext3/ext4 file system debugger
ofm2opl : convert Omega and TeX font-metric files to property-list files
passwd : change user password
cweave : translate CWEB to C and/or TeX
mft : translate Metafont or MetaPost code to TeX code for prettyprinting
...

mail

airtun-ng : a virtual tunnel interface creator for aircrack-ng
gst-launch-1.0 : build and run a GStreamer pipeline
passwd : change user password
cweave : translate CWEB to C and/or TeX
find : search for files in a directory hierarchy
thunderbird : Mail User Agent (MUA) and newsgroup/RSS client for X11 derived from the Mozilla suite.
...

Media Player

spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
update-grub : stub for grub-mkconfig
passwd : change user password
cweave : translate CWEB to C and/or TeX
avifix : fix header of AVI-file
airtun-ng : a virtual tunnel interface creator for aircrack-ng
...

virtualization

nohup : run a command immune to hangups, with output to a non-tty
passwd : change user password
cweave : translate CWEB to C and/or TeX
avconv : avconv video converter
airtun-ng : a virtual tunnel interface creator for aircrack-ng
update-grub : stub for grub-mkconfig
...

help us categorise commands