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
sftp : secure file transfer program
openssl : OpenSSL command line tool
...

shell

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

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
MAKEDEV : create devices
busybox : The Swiss Army Knife of Embedded Linux
startpar : start runlevel scripts in parallel
ncurses5-config : helper script for ncurses libraries
ppmtosixel : convert a portable pixmap into DEC sixel format
...

file

mkfs.ext2 : create an ext2/ext3/ext4 filesystem
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
fsck.ext3 : check a Linux ext2/ext3/ext4 file system
...

graphic manipulation

gimp : an image manipulation and paint program.
start-stop-daemon : start and stop system daemon programs
animate : animates an image or image sequence on any X server.
pamstretch-gen : use pamstretch and pnmscale to scale by non-integer values
tiff2rgba : convert a TIFF image to RGBA color space
sha1sum : compute and check SHA1 message digest
...

database

mysqlimport : a data import program
mysqld_safe : MySQL server startup script
find : search for files in a directory hierarchy
mysql_zap : kill processes that match a pattern
gnome-terminal.wrapper : is a terminal emulation application.
airtun-ng : a virtual tunnel interface creator for aircrack-ng
...

X

gnome-terminal : is a terminal emulation application.
xfreerdp : FreeRDP X11 client
xlsclients : list client applications running on a display
lame : create mp3 audio files
loadunimap : load the kernel unicode-to-font mapping table
pnmmargin : add a border to a portable anymap
...

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

loadunimap : load the kernel unicode-to-font mapping table
awk : pattern scanning and processing language
dvdrip : GUI for copying DVDs
sha1sum : compute and check SHA1 message digest
nohup : run a command immune to hangups, with output to a non-tty
nl : number lines of files
...

privacy

passwd : change user password
kerneloops : program to collect and submit kernel oopses to kerneloops.org
loadunimap : load the kernel unicode-to-font mapping table
chroot : run command or interactive shell with special root directory
tor : The second-generation onion router
iconv : Convert encoding of given files from one encoding to another
...

sound manipulation

audacity : Graphical cross-platform audio editor
gst-launch-1.0 : build and run a GStreamer pipeline
avconv : avconv video converter
pdb3.3 : the Python debugger
sha1sum : compute and check SHA1 message digest
jack_evmon :
...

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

passwd : change user password
loadunimap : load the kernel unicode-to-font mapping table
dvdrip : GUI for copying DVDs
sha1sum : compute and check SHA1 message digest
zipsplit : split a zipfile into smaller zipfiles
unrar : extract files from rar archives
...

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

pdb3.3 : the Python debugger
cweave : translate CWEB to C and/or TeX
cpp : The C Preprocessor
kerneloops : program to collect and submit kernel oopses to kerneloops.org
update-grub : stub for grub-mkconfig
gedit : text editor for the GNOME Desktop
...

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

sha1sum : compute and check SHA1 message digest
nohup : run a command immune to hangups, with output to a non-tty
lame : create mp3 audio files
start-stop-daemon : start and stop system daemon programs
iwlist : Get more detailed wireless information from a wireless interface
spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
...

mail

nohup : run a command immune to hangups, with output to a non-tty
ping : 6 send ICMP ECHO_REQUEST to network hosts
start-stop-daemon : start and stop system daemon programs
avconv : avconv video converter
jack_connect : JACK toolkit clients for connecting & disconnecting ports
airtun-ng : a virtual tunnel interface creator for aircrack-ng
...

Media Player

lame : create mp3 audio files
start-stop-daemon : start and stop system daemon programs
amarok : The audio player for KDE
gst-xmllaunch-0.10 : build and run a GStreamer pipeline from an XML serialization
sha1sum : compute and check SHA1 message digest
nohup : run a command immune to hangups, with output to a non-tty
...

virtualization

lame : create mp3 audio files
loadunimap : load the kernel unicode-to-font mapping table
sha1sum : compute and check SHA1 message digest
innochecksum : offline InnoDB file checksum utility
ping : 6 send ICMP ECHO_REQUEST to network hosts
start-stop-daemon : start and stop system daemon programs
...

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