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
fsck : check and repair a Linux filesystem
chown : change file owner and group
passwd : change user password
aireplay-ng : inject packets into a wireless network to generate traffic
fsck.ext4 : check a Linux ext2/ext3/ext4 file system
...

programming

strace : trace system calls and signals
MAKEDEV : create devices
busybox : The Swiss Army Knife of Embedded Linux
startpar : start runlevel scripts in parallel
find : search for files in a directory hierarchy
killall5 : - send a signal to all processes.
...

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

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
sha1sum : compute and check SHA1 message digest
tiff2rgba : convert a TIFF image to RGBA color space
...

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
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

ghostscript : Ghostscript (PostScript and PDF language interpreter and previewer)
ppdc : cups ppd compiler
pdb3.3 : the Python debugger
start-stop-daemon : start and stop system daemon programs
gnome-session : Start the GNOME desktop environment
foomatic-ppd-to-xml :
...

text manipulation

passwd : change user password
start-stop-daemon : start and stop system daemon programs
cut : remove sections from each line of files
grep : print lines matching a pattern
chcon : change file security context
airtun-ng : a virtual tunnel interface creator for aircrack-ng
...

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

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
gst-launch-1.0 : build and run a GStreamer pipeline
dh_installppp : install ppp ip-up and ip-down files
airtun-ng : a virtual tunnel interface creator for aircrack-ng
usermod : modify a user account
login : begin session on the system
...

file compression

pdb3.3 : the Python debugger
scp-dbus-service :
file-roller : archive manager for GNOME
lzcat : Compress or decompress .xz and .lzma files
airtun-ng : a virtual tunnel interface creator for aircrack-ng
nohup : run a command immune to hangups, with output to a non-tty
...

boot settings

tcmp3cut :
erb1.8 : an embedded Ruby language interpreter
start-stop-daemon : start and stop system daemon programs
ping : 6 send ICMP ECHO_REQUEST to network hosts
showkey : examine the codes sent by the keyboard
dbus-send : Send a message to a message bus
...

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
ping : 6 send ICMP ECHO_REQUEST to network hosts
start-stop-daemon : start and stop system daemon programs
dh_installppp : install ppp ip-up and ip-down files
spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
gst-launch-1.0 : build and run a GStreamer pipeline
...

font

iconv : Convert encoding of given files from one encoding to another
python2.7 : an interpreted, interactive, object-oriented programming language
kerneloops : program to collect and submit kernel oopses to kerneloops.org
loadunimap : load the kernel unicode-to-font mapping table
afm2tfm : convert Adobe font metrics to TeX font metrics
sha1sum : compute and check SHA1 message digest
...

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

nohup : run a command immune to hangups, with output to a non-tty
ping : 6 send ICMP ECHO_REQUEST to network hosts
subtitle2pgm :
svlc : , nvlc, rvlc, cvlc the VLC media player
spd-conf : A simple tool for basic configuration of Speech Dispatcher and problem diagnostics
update-grub : stub for grub-mkconfig
...

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
...

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