linux-cheatsheet.txt

``` 
      ____                               _                    _           
     / ___|___  _ __ ___  _ __  _ __ ___| |__   ___ _ __  ___(_)_   _____ 
    | |   / _ \| '_ ` _ \| '_ \| '__/ _ \ '_ \ / _ \ '_ \/ __| \ \ / / _ \
    | |__| (_) | | | | | | |_) | | |  __/ | | |  __/ | | \__ \ |\ V /  __/
     \____\___/|_| |_| |_| .__/|_|  \___|_| |_|\___|_| |_|___/_| \_/ \___|
                         |_|
 _     _                     ____ _                _       _               _   
| |   (_)_ __  _   ___  __  / ___| |__   ___  __ _| |_ ___| |__   ___  ___| |_ 
| |   | | '_ \| | | \ \/ / | |   | '_ \ / _ \/ _` | __/ __| '_ \ / _ \/ _ \ __|
| |___| | | | | |_| |>  <  | |___| | | |  __/ (_| | |_\__ \ | | |  __/  __/ |_ 
|_____|_|_| |_|\__,_/_/\_\  \____|_| |_|\___|\__,_|\__|___/_| |_|\___|\___|\__|
```             



###########
## GNOME ##
###########

Ctrl+Alt T — Terminal
Ctrl+Alt F — Firefox
Ctrl+Alt H — Home
Ctrl+Alt G — Gedit
Alt F12 — Run command
 
Alt F1 — Minimize window
Alt F2 — Toggle maximize window
Alt F3 — Toggle full screen
Ctrl+Alt D — Minimize all windows

Ctrl+Alt F1-F6 — Terminals (tty-s)
Ctrl+Alt F7-F12 — Xwindows
Ctrl+Alt Bksp — Restart X
Ctrl+Alt Del — Log out
Ctrl+Alt End — Shutdown
Super PgUp/PgDn — Switch workspace
Middle mouse button — Paste selected text


NAUTILUS/NEMO:
Ctrl L — Location, show path
Ctrl+Shift N — New folder
Ctrl H — Show hidden files


GEDIT:
Ctrl G — Find next
Ctrl+Shift G — Find previous
Ctrl+Shift K — Clear highlights


TERMINAL:
Ctrl+Shift C — Copy
Ctrl+Shift V — Paste
Ctrl+Shift T — New tab   
Ctrl+Shift W — Close tab     
Ctrl PgUp/PgDn — Switch tab
Ctrl +/- — Zoom
Ctrl D — Close terminal
Ctrl S — Scroll lock


BASH:
Keys when in emacs mode. You can switch to `vi` mode with `set -o vi` command.
Ctrl C — Interrupt, erase line
Ctrl A — Go to beginning of line
Ctrl E — End of line
Ctrl U — Copy line
Ctrl Y — Paste line
Alt . — Last argument
Ctrl R — Search trough history
Alt * — Show all matches for regular expression
Ctrl+Alt E — Show current line passed through alias, history and shell expansion
Ctrl X, Ctrl E — Edit command in editor
Ctrl P — Show last command (same as up arrow)



###############################
## AWESOME TERMINAL COMMANDS ##
###############################

========
PACKAGES:
========

dpkg — Low level package manager for Debian.
    -l — Lists installed packages.
    -i <package> (sudo) — Installs package from a package file.
apt-get — Advanced Package Tool built on top of `dpkg`. New command called 
        simply `apt` is also available. It merges the functionalities of 
        `apt-get` and `apt-cache`.
    update — Updates local list of existing packages.
    -u dist-upgrade — Upgrades by intelligently handling changing dependencies 
            with new versions of packages. To regularly update put this line 
            in `crontab`:  
            `apt-get update && apt-get -u dist-upgrade`. 
    upgrade — Same as dist-upgrade, but will not remove installed packages or 
            install new ones.
    install <package> — Also updates single package.
    remove <package> — Removes package but leaves its configurations.
    remove apt-listchanges — Useful when Debian can't find a package.
    purge <package> — Removes package and its configurations. Run `apt-get 
            autoremove` after to remove all dependencies that are not needed 
            anymore.
    autoremove — Removes unneeded packages.
    source <package> — Downloads code.
    build-dep <package> — Installs the build dependencies.
    --yes — Answers with 'yes' to most questions (Except the ones that can have
            potentially harmful consequences).
    --force-yes — Answers 'yes' to all questions (Not recommended).
apt-cache — Queries the APT's internal database. 
    search <keyword> — Searches packages like `apropos`, but globally.
    show <package> — Shows package info like version, dependencies, etc.
    showpkg <package> — Similar, but also shows the packages that depend on the
            searched package (reverse dependencies).
    policy <package> — Shows installed and remote version.
apt-file — APT package searching utility.
    search <file> — Search in which package a file is included.
    update — Updates local list of package contents.
aptitude — Enables package browsing (skin for apt-get).
    search '~i!~M' — Lists installed packages that were not installed as a 
            dependency, with short description of each.
    search <package> — Package search.

winetricks — Installs wine applications.
update-alternatives — Maintains symbolic links determining default commands.
unattended-upgrade — Automatic installation of security upgrades.


COMMANDS:
apropos <cmd> — Searches the manual page names and descriptions (use quotes 
        for phrases).
    -a — Matches all keywords.
whatis <cmd> — Displays one-line manual page description.
whereis <cmd> — Locates the binary, source, and manual page files for a 
        command.
which <cmd> — Locates only the binary of a command.
wtf — Translates acronyms and filename suffixes.


INSTALL MANTRA:
```
./configure --help
./configure
make
sudo make install
```

=======
GENERAL:
=======

su — Switches user.
    - <user> — Switches to user.
    - — Switches to root.
man — Help on commands.
    <section> — Section numbers: 1. Programs, 2. System calls, 3. Library calls,
            4. Special files, 5. File formats, 7. Miscellaneous, 8. System 
            administration commands
echo — Prints passed text.
    -n — Does not add newline at the end.
    -e — Enables interpretation of backslashed letters.
xargs <cmd> — Passes output from one command to arguments of another:  
        `echo -a | xargs ls`
    -t — Echoes the command before executing it. 
    -p — Echoes command and asks for confirmation before execution.
    -0 — Input items are separated by null character instead of space.
tee <file> — Sends output of a program to specified file and to standard 
        output:  
        `<cmd_1> | tee out_1.txt | <cmd_2>`
    /dev/tty — Sends output to terminal and to standard output
expr — Evaluates passed expression.
    1 + 1 — Prints `2`.
bc — Evaluates input. It's basically a calculator, but also provides some 
        control commands.
    echo 1 + 1 | bc — Prints `2`.
    echo "scale=5;3/4" | bc — Prints `.75000`.
sh — Runs command interpreter (shell). Can run a script even if not executable.
    -c '<commands>' — Starts new non-interactive shell and reads commands from 
        arguments instead of `stdin`.  
        To append lines to system configuration file run:  
        `sudo sh -c 'echo "<text>" >> <file>'`
bash — Runs bash command interpreter (shell).
    -c — Reads commands from arguments instead of `stdin`.
    -n <script> — Checks script for errors.
    -x — Prints commands before execution. Useful for debugging.
gcc — Gnu C compiler. Run `g++` for C++ code.
    -w — Supresses warnings (Only prints errors).
    -Wall — All warnings.
    -g — Compile for debugging.
    -std=<std> — Sets the standard. Suported standards for C are:  
        `c90`, `gnu90`, `c99`, `gnu99`, `c11` and `gnu11`.  
        Suported standarts for C++ are:  
        `c++98`, `gnu++98`, `c++11` and `gnu++11`.  
        `gnu90` and `gnu++98` are the default options.
    -O<level> — Optimization level. `0`: Reduce compilation time (default),
        `1-3`: - Level of optimization, `s` - Optimize for size, `g` - Optimize
        debugging experience.
run-parts <dir> — Runs all scripts or programs in a directory.
date — Tells and sets date and time.
    -s <string> — Sets date.
    +%T -s "10:13:13" — Sets time.
timedatectl — Controls the system time and date.
    set-timezone CET — Sets timezone.
cal — Calendar
xclip — Copies to clipboard.
mkfifo <pipe> — Creates named pipe during that shell session.
mkisofs — Creates a DVD/CD image.
genisoimage — Creates a DVD/CD image (Debian).
cdrecord — Writes to a CD/DVD.
acpi — Checks battery.
fdisk -l (sudo) — Shows partitions. 
shutdown — Closes down the system at a given time.
    now — Takes you to the single user mode.
    -h now — Begins the shutdown procedure, same as `halt` and `poweroff`.
    -h 11:50 — At 11:50.
    -r now — Same as `reboot`.
make — Utility that maintains groups of programs.
    -q — Doesn't run any commands, just returns `0` exit code if everything is
            up to date or non-zero otherwise.
    -B — Unconditionally makes all targets.


FILES:
ls  -d — List directory names instead of contents
    -S — Sort by size 
    -t — Sort by time
    -1 — One file per line
    ./* — Ls one level deep
    -i — Get inode number of file (file id). Use `sudo find / -inum <number>` to find all links that point to same file.
cp  -i — Interactive (Prompts before overwrite)
    -v — Verbose (Explains what is being done)
    -R — Copy directories recursively
    -p — Preserve mode, ownership and timestamps
    --preserve=all — Also preserves context, links and xattr
rm  -i — Interactive (Prompts before every removal)
    -v — Verbose (Explains what is being done)
    -f — Force remove (Does not prompt, useful if `rm` is aliased with `-i`)
    -R — Removes directories and their content recursively 
mkdir  -p — Make parents if needed
ln — Makes links to the files
    -s <file> <link> — Makes symbolic link. If you want to use relative paths you must be in links directory !!!!!!!!!!!!!!!!!!!!!!
df  -h — Displays humanly readable free disk space
du  -s <dir> — Directory size
mc — Midnight commander
    Alt o — Open parent dir in another panel
    Ctrl o — Switch to bash
find <dir>  -name <file> — Search by name
    -regex <regex> — Use regex for name search
    -not — Insert before other options to negate
    -maxdepth <levels> — Descend only to levels deep
    -samefile <file> — Find all hard links of a file
    -xdev — Don't descend directories on other filesystems
    -inum <inum> — Find files with the inode number
    -type <f|d|b|...> — Find files of type
    -delete — Delete found files
    -exec <cmd> {} \; — Find files and execute command for every found file. `{}` is replaced with filename
    -exec <cmd> {} + — Find files and execute command with all filenames in place of `{}`
    -atime +/-n — Find files that were last accessed less or more than n days.
    -print0 | xargs -0 <cmd> — Sends found files to a command as parameters. Uses `NUL` character as separator, necessary for filenames with spaces 
locate <regex>  — Similar as `find` but using index
    -i — Ignore case
    --regex — Interprets all patterns as extended regex
    -0 | xargs -0 <cmd> — Sends found files to a command as parameters.
updatedb (sudo) — Update locate index 
md5sum — Prints md5 sum hash of a file
read — Read single line from standard input 
  -n 1 — Print after reading one character
  -s — Do not echo input coming from terminal
shred — Securely remove files
file — Determine file's type
tree — Ls in a tree-like (hierarchical) format
install — Copy files and set attributes
gpg — Decrypt file with password
    -c — Encrypt
mktemp — Create a temporary file or directory in `/tmp` and returns it's name.
rename  s/<from>/<to> <files> — Renames multiple files using `sed` syntax
rsync — A fast, versatile, remote (and local) file-copying tool
        -Hbaz -e ssh — `<src_dir> <user>@<host>:<dest_dir>` - Backs up the 'src-dir':
        `-H` preserves hard links, `-b` renames preexisting destination files (back up), `-a` preserve everything except hard links and `-z` compresses.
        cmp — Compares two files, similar to diff but also for binaries
stat — Displays files status
    -c%X — Time of last modification of the file 
readlink  -f — Follow link recursively and print files path
xdg-open — Open file with default application for the file type
dialog — Display dialog box from shell script
watch — Execute command periodically


ARCHIVES:
dtrx  <archive> — Universal archive extractor
tar — xvzf <file>.tar.gz (.tgz) — Decompress and detar
    xvjf <file>.tar.bz2 — Decompress and detar
    -cf <archive>.tar <files> — Compress
unzip  \*.zip — Backslash is necessary so that bash doesn't expand the `*`
    -d <dir> — Extract into directory (create if doesn't exist)
zip  -r <archive> <dir> — Compress whole directory recursively.
    -g <archive> <files> — Add files to existing archive (grow).
unrar  e — Extract files from rar archive
zcat — Cats gziped file


TERMINAL MULTIPLEXERS:
screen — Switch between multiple virtual terminals (useful in ssh). Prefix for
    a command is `Ctrl a`.
    c — New terminal, 
    n — Next, 
    p — Previous, 
    a — Go to beginning of line,
    | — New region vertically,
    S — New region horizontally,
    tab — Move to next region,
    Q — Close all but selected region,
    X — Kill the current region,
    esc — Enter copy/scrollback mode -> space: start/stop marking,
    ] — Paste,
    k — Kill window,
    t — Show time and avg CPU load
tmux — Terminal multiplexer, better screen. Prefix for a command is `Ctrl b`. 
    Most commands are the same as in `screen`.
    ls — Shows running sessions
    attach [-t <no>] — Attach to running session
    d — Detach from currently attached session  
    pgup — Enter in copy mode and pageup, 
    [ — Copy mode, 
    ] — Paste,  
    " — Split horizontally, 
    % — Split vertically 


====
BASH:
====

"$x" — ALWAYS PUT DOUBLE QUOTES AROUND VARIABLE!!!!!!!!!!!!!!! 
       All variables in bash are global!!!!!!!
"$*" — Combines all the arguments into single word, separating them with first character of IFS variable. If IFS is not set, space is used. If IFS is null, no separator is used!!!!!!!!! No args provided will result in one empty string being passed on!!! 
"$@" — Use this instead!!!!! Will retain arguments as-is, so no args provided will result in no args being passed on. This is in most cases what you want to use for passing on arguments.
    Google: "$@" is right almost everytime, and $* is wrong almost everytime.
"$#" — Number of arguments
"$1" — First argument
"$0" — Name of the script
$'\n' — String literal with escape sequences (there is a backslash before n)
    If you want IFS to be a new line (useful with for loop) you need to: `IFS=$'\n'` - The dollar forces substitution!!!!!
    Also if you want 'while read line; do...' to preserve leading spaces and tabs, you need to set IFS=""
$? — Exit code of last command (0 - Success)
Ctrl-Z, kill %% — Kill looping bash script

test <expr> — Same as `[ <expr> ]`. Returns zero exit status if true.
    -n — Is string non empty
    -z — Is string empty
    -a — And
    -o — Or
    = — Strings are equal
    -nt — File newer than
    -ot — Older then
    -d — Directory exists
    -e — File exists
    -f — Is a regular file
    -h — Its a symbolic link
    -r — Has read permission
    -w — Has write permission
    -x — Has execute permission
[[ <expr> ]] — Same as `[`, but without word splitting and filename expansion. And with additional operators: `&&`, `||`, `<`, `>` (lexicographic less, more), and also regular expression matching.
=~ — Regex comparison operator: `[[ "$HOST" =~ ^user.* ]]`
let <expr> — Executes expression: let a="$b"+2

$(command) — Same as `command`
eval <variable> — Execute string as command
$RANDOM — 0 - 32767
input=`cat` — Getting standard input
- — In place of a file name means standard in or out
set -o vi — Set line editing to vi mode
pushd . — Put current dir on stack
popd — Pop dir from stack
cd - — go to last dir
source <script> — Run script: for example source /etc/profile (same as . <cmd>)
#!/bin/bash — Good practice to insert at beginning of a bash script
export  PATH="$PATH:<dir>" — Adds new directory to path environment variable.
read  -p <message> — Prompt for user input
var=${1:-"<default>"} — Setting variable with default value if $1 is empty
getopts — Parse parameters/arguments, builtin
getopt — GNU version is even better then getopts, not a builtin
while read line; do <commands>; done < <file> — Read from file line by line
    -r — Do not treat backslashes as escape characters
complete -F <completion_function> <cmd> — Set completion function for command
complete -p <cmd> — Print the completion function for command
compgen -c <pattern> — Print all completions for pattern
help <builtin> — Display information about builtin command
wait — Wait for all background processes to end


SAFETY:
set — -e — Exit if any command fails
    -u — Exit if referencing undefined variable
    -o pipefail — If any command in a pipeline fails, its return code is used as the return code of the whole pipeline
IFS=$'\n\t' — Remove space from the default Internal Field Separator


HISTORY:
sudo !! — Run the last command as root 
␣<cmd> — Execute a command without saving it in the history
!<cmd> — Run last command that starts with cmd


REDIRECTIONS:
<cmd> 2> /dev/null — Redirect error output to `null`
<cmd> &> /dev/null — Redirect both standard and error output to `null`
<cmd> >&2 — Write to stderr
<cmd> 2>&1 | less — Add stderr to stdout and print it with less (useful for gcc)


ARRAYS AND LINES:
Reads line by line from variable. To preserve spaces use `IFS=`.
```
while IFS= read -r line; do
    echo "... $line ..."
done <<< "$list" — 
```

${a[1]} — Value of the second element of the array
for c in ${a[@]} — Iterate over array
${varname:offset:length} — Get substring: `s="aeiou"; ${s:3:1} -> o`
${#var} — Length of a var 
${#name[subscript]} — Length  of the element
${#name[@]} — Length  of the array


ALIASES AND FUNCTIONS:
alias — Print all aliases
    <name> — Print alias
    <name>='cmd' — Set alias
command <cmd> — Executes original command, bypassing any aliases or shell functions that may be defined for command
\<cmd> — Temporarily disable alias (call original)
type <cmd> — Will tell you what is command aliased to or if it is a builtin, function or a command
    -P just check commands
declare -F — Print function names
declare -f — Print functions


====
TEXT:
====

PRINT:
head — -n-<num_of_lines> — Print all lines but the last n
    -c <num_of_chars> — Print first c characters
tail — -n+<line_num> — Start at line number
    -f — Do not stop printing (follow)
cat — -n — Number all lines
    >> file — Simplest text editor (great for pasting)
less  &<patt> — Display only lines with pattern
    -N — Show line numbers
    -~ — Do not show `~` after `EOF`
    +G — Tells less to start at the end of the file
    +F — Follow the input (to scroll up first press ctrl+c)
    -F — Or --quit-if-one-screen
    v — Opens editor defined in `$VISUAL` or `$EDITOR`
    :n — Examine the next file
    <, > — Go to home, end
wc — Count lines, words and characters


EDIT:
sudo -e <file> — Edit file as sudo
tr <from> <to> — Translate characters
    -d — Delete characters
cut <file> — Removes columns from each line of files
    -d ':' -f 1,7 /etc/passwd — Only show the username and the shell
sort — Sorts lines
    -u — Uniq, removes duplicates
    -t — Set delimiter for fields (default is space)
    -k — Select by which field to sort 
uniq — Removes adjacent duplicates
    -d — Intersection
    -u — Difference
column — Columnate text
    -t — Create a table
shuf — Shuffle input lines
tac — Concatenate and print files in reverse (reverse `cat`)
join — Join lines of two files on a common field
colrm  [from [to]] — Removes columns
seq <number> — Output numbers from 1 to number
ispell, aspell — Interactive spell checker
basename <path> — Strips directory from path
    -s .<suffix> — Also strip suffix
    -a — Process multiple filenames
dirname <path> — Strip last component from path
fmt — Produce roughly uniform line lengths
fold — Wrap each input line to fit in specified width
paste — Glue two documents side by side
sed — 's///g' — Substitute every occurrence in line, not just the first one
    's///I' — Ignore case
    -r — Extended syntax, for `+`, `?`, ... Also you shouldn't escape the parenthesis
    -r 's###e' — Execute match as a command
    -i <file> — Will make changes directly to the file (in place)
    -u — Unbuffered mode (processes input immediately)
        -n l — Print escape sequence (keycode) of a pressed key
expand — Convert tabs to spaces
    -t <number> — Set number of spaces (default is 8)
    -i — Do not convert tabs after non blanks


DIFF:
diff — -u <files> — Unified format
    --brief -r — Compare two directory trees
colordiff — Version of diff with colors
sdiff — Two files side by side
comm — Compare two sorted files line by line
patch — Apply a diff file to original
    patch < patch.diff — Apply patch
    diff -u <old_file> <new_file> > patch.diff — Create patch


SEARCH:
grep <patt> <file> — -v — Inverse
    -n — Line numbers 
    -w — Whole word 
    -A<num> — Print also num lines after
    -B<num> — Print also num lines before
    -r — Recursive 
    -o — Print only matching part
    -P — Perl notation with additional operators such as: `\\t`, `+` and `?` (non-greedy!!!!).
    -i — Ignore case 
    -I — Do not process binary files 
    -l — Just print files with matches 
    -L — Just print files without matches
    -e <patt> — Necessary to put before pattern if it starts with `-`!!!!!!! or if you want multiple patterns.
    | wc -l — Count occurrences
    --line-buffered — Processes input line by line instead of in bigger chunks
look — Display lines beginning with a given string
strings — Print all text parts of binary file


CONVERT:
todos, fromdos — Convert line endings form/to windows format (package tofrodos)
enscript — Converts text files to postscript, rtf, HTML
gs — Ghostscript: postscript and PDF language interpreter and previewer
pdftohtml — Pdf to html
pdftotext — Pdf to text
libreoffice — New Openoffice
figlet — Display large characters made up of ordinary screen characters (Ascii art)
toilet — Similar (Ascii art)
cproto — Generates C function prototypes (declarations)


EDITORS:
nano — Simple text editor.
    /etc/nanorc — Config file.
    /usr/share/nano/<lang>.nanorc — Syntax highlight files.
    Alt + / or ? — Go to last line.
fte — Cool text editor with CUA (IBM)-shortcuts
diakonos — Simple terminal text editor with ctrl-c for copy
pyroom — Distraction free writing (gui)


=======
NETWORK:
=======

whois — Info about domain
host <ip/hostname> — DNS lookup utility
nslookup — Same interactively
dig — Same, lot of options
hostname — Prints/sets computer name, to set it permanently edit `/etc/hostname` and `/etc/hosts`
netstat — Displays contents of /proc/net files,  status of ports...
    -r — Show routing table
    -i — Show interfaces
arp — Manipulate the system ARP cache (IP -> mac)
route — Tool used to display or modify the routing table
    add default gw <ip> — Change the default gateway
    should DNS not be configured correctly on your machine, you need to edit `/etc/resolv.conf` to make things work
ifconfig eth0   down/up (sudo) — Turn network interface on/off 
    <ip> netmask <mask> up — Set ip and mask
ifup eth0 — Will bring eth0 up if it is currently down.
ip  link show — List network interfaces
    link set dev eth0 up — Bring interface eth0 up or down
    addr show — List addresses of interfaces
    route add default via <ip> — Set default gateway
traceroute, traceroute6, traceroute6.iputils — Traces route
tracepath, tracepath6 — Similar (iputils package)
mtr — Combines the functionality of the traceroute and ping
findsmb — List info about machines that respond to SMB name queries - Windows based machines sharing their hard disks
/etc/services — List of internet services with their port numbers
NetworkManager — Network management daemon, configuration file is in /etc/NetworkManager/NetworkManager.conf 
nm-tool — Prints info 
nm-online — Is network connected 
nmcli — Command-line tool for controlling NetworkManager
nc — (netcat) It can open TCP connections, send UDP packets, listen on arbitrary TCP and UDP ports, do port scanning...
ncat — Concatenate and redirect sockets
ethtool eth0 — Show status of eth0
    -S — Statistics
    -s — Change settings (speed, duplex,...)
ss -tupl — List internet services on a system
    -tuo — List active connections to/from system


WIRELESS:
iwconfig — Sets the wireless configuration options basic to most wireless devices
iwlist wlan0 — <option> — Displays current status information of a device, more detailed then iwconfig
        scan (sudo) — List wireless networks in range 
iwspy — Sets the list of IP addresses in a wireless network and checks the quality of their connections
iwpriv — Accesses configuration options specific to a particular device
rfkill  list — Show wireless adapters (wifi and bluetooth)
    block/unblock <dev_num> — Block/unblock wireless device
iw dev wlan0 — link — Show link status of wlan0
        set biterates <standard> — Manually set interface speed
        scan (sudo) — List wireless networks in range 
wavemon — Monitor wireless connection link quality


========
INTERNET:
========

mutt — Mail client
sftp — Secure ftp
sshd — (openssh-server) ssh server deamon, on Windows service is named 'CYGWIN sshd'

/etc/init.d/ssh restart (sudo) — Restart sshd (ssh deamon) 
/usr/local/etc/init.d/openssh start (sudo) — Start openssh deamon 
ssh-keygen -t rsa -C <email> — Generate rsa key pair, keys are stored in ~/.ssh

ssh — SSH client
    <user>@<address> "mpg321 -" < <file>.mp3 — Stream audio over ssh
        enter ~. — Kill unresponsive session
scp — Securely copy files over network. Example: `scp <local_file> <user>@<host>:~<remote_file>`
wget — Download files from WWW
    -O — Specify output file
    -c — Continue downloading unfinished file. Can also use wildcards, but use single quotes around url. 
    -r -l1 --no-parent -A.gif — Recursively to the depth of one ignoring references to the parent directory and all gifs.
curl — Similar
    -qO - — Writes to standard output + quiet 
    -i — Urls specified by standard input
transmissioncli — Torrent terminal client 
    -d — Download limit (kB/s)
    -u — Upload limit 
youtube-dl — Download from YouTube
noip2 — Dynamic dns update client
rdesktop — Remote Desktop Protocol client
tin, nn — Usenet client
nrss — Rss feed reader


BROWSERS:
lynx — Terminal web browser 
    -cmd_log=<file> — Write keystrokes to script
    -cmd_script=<file> — Read keystrokes from script
    -syslog-urls — Log requested URLs with syslog.
    -dumb — Prints txt to stdout 
    -crawl — Same, turns numbers off
    -source — Prints html to stdout
    -l — Add the current link to your bookmark file 
    a — Save the address of a document or link to a bookmark file, by default ~/lynx_bookmarks.html
    o — Options (you can select vim mode)
    ctrl+n — Scroll down two lines
    ctrl+p — Scroll up two lines
    ctrl+p — Previous line
    crrl+n — Next line
elinks — Another web browser (has menus)


HACKING:
nmap — -sP 192.168.1.1-3 — Network scanning
    192.168.1.3 -p100-139 — Port scanning
    -O 192.168.1.3 (sudo) — Scanning os 
tcpdump (sudo) — Sniffer (show network traffic) 
    -l — Buffered output (for piping to less, etc.)
ettercap — Multipurpose sniffer/interceptor/logger for switched LAN (can detect man in the middle, denial of service, DNS spoofing)
driftnet — Picks out and displays images from network traffic
kismet — Wireless 802.11b monitoring tool
aircrack-ng — Wireless WEP/WPA cracking utilities
Cain & Abel — Password recovery tool for Microsoft Operating Systems
dnsniff — Warious hacking tools: 
    arpspoof — For man in the middle attack
    dsniff — Password sniffer for several protocols, ...
ip link set eth0    promisc on — Set network interface to promiscuous mode
            multicast off — Set multicast off


======
SYSTEM:
======

meta, system info — In cinnamon
uname -a — Print system info, kernel version
cat /etc/issue — Show name and version of distribution

init — Upstart init daemon job configuration
telinit — Change system runlevel
dmesg — Print the contents of your bootup (startup) messages displayed by the kernel. This is often useful when debugging problems
getconf -a — Print all system configuration variables
nohup <cmd> — Run a command immune to hangups, runs even after the shell is closed (writes output to nohup.out)
    &>/dev/null & — Run a command immune to hangups in background, do not save output
wmctrl — X Window Manager
awesome — Tiled window manager
    -k — Check configuration script for errors

busybox <cmd> — Combines tiny versions of many common UNIX utilities into a single small executable. (1.5 Mb)
mono — .NET support


USERS:
users — Prints logged in users
who — Logged in users, more data
w — Logged in users, also what are they running
vipw — Edit password file
vigr — Edit groups file
umask —  the umask is a value set by the shell. It controls the default permissions of any file created
usermod <user> — Modify user account information
    -l <new_name> <old_name> —
    -c "<new_real_name>" <user> —
    -d /my/new/home <user> — Change location of the users home
    -m -d /my/new/home — Also move the files
useradd <user> — Add user
adduser <user> — More high level (use `adduser <user> sudo`  after to add user to sudo group)
    --system — Create system user (can not log in) 
    <group> — Add user to group (only takes effect after login!!!)
groups <user> — What groups user belongs to
userdel -r <user> — Remove user and his home dir
deluser  -remove-all-files <user> — More high level, removes also files outside home, cron jobs, itd
passwd <user> — Change password


FILE SYSTEMS:
mkfs — Build a Linux filesystem
mke2fs — Create a ext filesystem
mkswap — Set up a swap area
parted — Partition manipulation program
    -l (sudo) — List partitions 
fdisk — Manipulate disk partition table
    -l (sudo) — List partitions 
disks — Nice GUI partition tool
mount — List all mounted devices (to get list of devices use `fdisk -l`)
    <device> <path> — For example mount /dev/hdc2 to /mymedia
lsattr — List file attributes
chattr — Change file attributes
rkhunter -c — Checks if it can find any rootkits under the system
ntfsundelete — Undelete files on NTFS partition 


LOGGING:
last — When various users have logged in or out. This includes information on when the computer was rebooted.
lastlog — Displays a list of users and what day/time they logged into the 
    system.  
    To get all failed logins run:  
    `cat /var/log/auth.log | grep "failed password" -i`.
rsyslogd —  manages all the logs on your system
    closelog, openlog, syslog, vsyslog -> library calls that send messages to the system logger
logger — Makes entries in the system log
zeitgeist — Activity logger


LOAD:
tload — 'graphic' representation of system load
top — Show processes by resource consumption
    <, > — Change resource
htop — Better top
free -tm — Displays memory statistics 
    -s <seconds> — Continuously display
vmstat — Performance of system components / virtual memory statistics
sar — System activity information
iostat — Disk usage
time <cmd> — Time a execution of a command
perf — Profiler


TRACING:
auditd — System call auditing (package)
ausearch — Querys the audit logs
autrace — Traces a specific process
auditctl — Controls the behavior of the auditd server
strace <cmd> — Trace system calls and signals. All printed system calls can be looked up by `man`!
    -s — Maximum string size we want printed (default is too short, 2000 is OK)
    -f — Also follow children
    -p <pid> — Attach to process
    -o <file> — Write output to file
    -c — Count/aggregate
    -T — Time the execution of each call
ltrace — List library calls made by command
lsof — List open files with file descriptors
    -p <pid> — Open files by process
    <path> — Open files in path
lsmod — Show which kernel modules (drivers) are loaded
modinfo <module> — Get more information about kernel module


HARDWARE:
lshw (sudo) — List all hardware 
lspci [-tv] — Show pci info
lsusb [-tv] — Show usb info
lscpu — Print CPU information
dmidecode -q — Display bios/dmi information like ram size/type,
    max ram, computer model name, cpu information.
smartctl  -A /dev/sda — Show disk usage info
hdparm  -tT /dev/sda — Do a read speed test
badblocks  -s /dev/sda — Check for bad blocks
fstrim -v / — Discard unused blocks, useful for ssd-s
sensors — (lm-sensors) hardware monitoring tool, temperature, fan speed
pwmconfig — (fancontrol) set fan speed


TERMINAL:
tty — Print the file name of the terminal connected to standard input
stty — Change and print terminal line settings
openvt —  run a program on a next available tty
script — Makes a typescript of everything printed on your terminal. Ctrl-d to stop recording.
setterm — Set terminal attributes
    -cursor off/on — Set cursor on/off
gpm — Enable mouse for tty


KEYS/CHARACTERS/FONTS:
IN X:
xmodmap — Remap keys
setxkbmap -layout us — Set us keyboard layout
xev — Get keycodes of pressed keys
xset — User preference utility for X
    -r — Turn key autorepeat off 
    r — Turn key autorepeat on
X NOT NECESSARY:
loadkeys <country_code> — Load key mapping 
showkey — Get keycodes of pressed keys
setfont <font> — Set console font
    /usr/share/consolefonts/Uni2-VGA16.psf.gz — For example
    /etc/default/console-setup — contains the default settings 
jfbterm — Enable unicode characters in terminal
echo -en "\e]PC7373C9" — Change blue color in tty (first numeral after P means slot, and others shade)


=========
PROCESSES:
=========

ps --forest — View hierarchical view of processes
    v — Virtual memory 
    --sort <field> — Sort by field 
pstree — Similar
pgrep <pattern> — Prints PIDs of processes containing pattern
    -l — Also print process name
pkill <pattern> — Kills every process that contains pattern in name
kill    <pid> — Sends TERM signal to process
    -kill <pid> — Sends KILL signal meaning force quit, data will be lost
killall — Uses name instead of pid
skill — Sends signals to command/user/tty or report process status
    -stop <user> — Stop all of the users processes
    -cont <user> — Continue all users processes
nice — Sets the priority for a process (from max of -20 to min of 20)
    -20 <cmd> — Execute command with maximum priority
renice — Changes the priority of an existing process
    +20 <pid> — Change processes priority to lowest level
snice — Works very similarly to skill
    -10 -u root — Increase the priority of all root's processes
pmap — Report memory map of a process (mapped file)


JOBS:
Ctrl z — Put job into background
jobs — Prints currently running job
bg <job_id> — Put job in background
fg <job_id> — Bring job to the foreground
%n — Job number n
%s — Job whose command line starts with s
%% — Current job
%- — Previous job


SCHEDULED COMMANDS:
at — Executes command at a particular time
    at 21:30 / at now + time / at -f shell_script now + 1 hour
    echo "ls -l" | at midnight
atq — List jobs currently in 'at' queue
atrm — Remove a job from the 'at' queue
crontab -e — Schedule commands for repeating execution 
cron — Daemon that executes scheduled commands 
    sudo service cron status — Print status of cron
    sudo service cron [stop|start|restart] — Stop, start, or restart cron deamon
    sudo vim /etc/default/cron — Set logging lever
    cat /var/log/cron — Print log
anacron — Like cron but it catches up with tasks next time the computer gets turned on


SERVICES:   
service — Allows you to start, stop or restart a service (it runs a script in /etc/init.d folder)
    -f sshd — Restart the ssh server
    httpd status — Get status of apache
    --status-all — Print status of all services
    You can also execute the shell script directly from /etc/init.d folder like: /etc/init.d/httpd stop. 


SYSTEM RUNLEVELS:
runlevel — Output previous and current runlevel
    0 — Shuts down the system
    1 — Administrative single-user mode
    2 — Same as 3 but without networking / multiuser with X server
    3 — Text mode state (ctrl+alt+F1) / User defined
    4 — User defined
    5 — X-window mode (ctrl+alt+F7) / User defined
    6 — Reboots
    S — Single user mode


==========
MULTIMEDIA:
==========

AUDIO:
alsamixer — Set audio level (curses)
amixer — Set audio levels (command line)
rmmod pcspkr (sudo) — Disable pc-speaker, beep 

cmus — Music player (can be controlled from outside)
mplayer — Movie/music player
mpg321 — Plays mp3
ogg123 — Plays ogg
aplay — Plays audio
play — Plays audio
arecord <file>  — Command line audio recorder and player
    -f <format> — Set file format (cd)
    -d <seconds> — Set duration
    -f cd -d <seconds> -t raw | lame -x -r — Out.mp3 — Capture audio that is playing and convert it to mp3
id3v2 -l — Lists all files tags
sound-juicer — Cd ripper
xfburn — Cd burner
traverso — Simple daw

BITMAP:
display — Displays an image
montage — Creates a montage from images
    <input_file/s> -set label '%t' <output_file/s> — Labels images
convert <old> <new> — Converts file format (imagemagick)
import — Captures screen-shots from the X server
mogrify — Edit image
gocr — Command line text recognition tool
ocrad — Command line text recognition tool
ppmforge — Creates picture of random planet or clouds
gnuplot — Interactive plotter: plot [-10:10] sin(x)
    -p — Leave plots open after exit
    plot <file>.dat — Plot data from dat file
fbi — Display images inside tty

VIDEO:
ffmpeg -i <file_in> <file_out> — Video and audio format converter. Has been replaced by avconv
avconv -i <file_in> <file_out> — Video and audio format converter (libav-tools)

openshot — Gui movie editor 
openmovieeditor — Gui movie editor 
aview, asciiview — ASCII art image viewer and video player



##########################
## AWESOME DEBIAN FILES ##
##########################

BASH:
~/.bashrc — Executed at every shell startup, user specific
/etc/bash.bashrc — Executed at every shell startup, all users
~/.profile, .bash_profile, .bash_login — First file found executed at login, user specific 
/etc/profile — Executed at login, all users (put PATHS here)
/etc/rc.local — Last startup script executed, runs command as su


HOME:
~/.Xmodmap — Keyboard map


BINS:
/bin — Key programs like ls, cat, bash, ...
/sbin — Key programs for system management like ifconfig, mkfs, fdisk, ...
/usr/bin — Distribution managed programs
/usr/sbin — Distribution managed system programs
/usr/local/bin — User programs not managed by the distribution package
/usr/local/sbin — User system management programs, not managed by the distribution package


GENERAL CONFIG:
"Edit To Configure" or "Editable Text Configuration".
/etc/mailcap — Default programs for extensions 
/etc/passwd — Users 
/etc/groups — Groups 
/etc/default — Boot script parameters that the end user or administrator is likely to change.  
    /console-setup — Set console (tty) character set, font size, ...
/etc/fstab — Filesystem table. To mount drive at startup, create dir in `/media` and append line like this :
    `/dev/sda1   /media/data   ntfs   user,fmask=0111,dmask=0000   0   2` (Check `man fstab` for details).
/etc/alternatives — Links to default application versions (here you can change the default Java JDK)
/etc/issue — Name and version of distribution
/etc/fstab — Automatic mounts are handled by configuring the file
/etc/sudoers — Lists of users and the commands they can run with sudo (needs to be edited with visudo command)
/etc/apt  /sources.list — List of places where to look for packages


SERVICES:
/etc/init/, ~/.init/  Init — Upstart init daemon job configuration
/etc/init.d — Folder with service scripts, that get executed at start and end
    /halt — Runs at the end 
/etc/rc<level>.d — Startup scripts for different runlevels - Links to scripts in /etc/init.d - S85httpd -> S means startup, K is for stop. (To disable service just change S for K)
/etc/rc.local — Last initialization file executed - Put your commands here

/etc/init/ssh.conf — Sshd config
/etc/ssh/sshd_config — Sshd config
/etc/crontab — System-wide crontab
/etc/cron.hourly, /etc/cron.daily, ... — Links to scripts that will execute periodically. Scripts within a cron directory are run alphabetically.
/etc/rsyslog.conf | rsyslog.d/50-default.conf — Log conf (need to restart rsyslogd after edit)
/etc/syslog.conf — Configuration information for syslogd 


NETWORK:
/etc/resolv.conf — Dns information
/etc/sysconfig  /networking/devices/ifcfg-eth0 — Use ifcfg to configure a particular interface
/etc/services — List of internet services with their port numbers
/etc/NetworkManager  /NetworkManager.conf — Configuration file


PROC: 
Various information about the system.
/proc/cpuinfo — Information about the CPU
/proc/modules —  information about which kernel-modules are loaded on your system
/proc/net — Network related
    /route — Routing table
    /netstat — Displays contents of /proc/net files
/proc/iomem — Neat memory map
/proc/partitions — Partitions info
/proc/acpi  /battery/BAT1/info — Battery info
    /ac_adapter/ACAD/state — Adapter info
    /wakeup — List of devices that can wake up your machine via acpi
    sudo sh -c "echo USB1 > /proc/acpi/wakeup" — Enable device USB1 to wakeup computer from sleep/suspend
/proc/net/wireless — Wireless connection info


USR:
"Unix System Resources"
/usr/lib  /jvm — Java JREs and JDKs
/usr/share  /man — Man pages
    /bash-completion — Bash completion functions


SBIN:
The "system-administrator's bin file".
Hosts programs that would be in /bin if they didn't have "root-only" access permissions.


VAR:
"Variable"
/var/log — System logs in here
    /auth.log — Logins
    /syslog — Most of the rest of the logs 
/var/spool — Contains data which is awaiting some kind of later processing


BOOT:
Kernels.
/boot/grub/menu.lst — Grub configuration file
/etc/default/grub — Grub configuration file



###########
##  GIT  ##
###########

GIT MANTRA:
```
git init
git add <file> OR git add .
git status
git commit -am "<commit_message>"
```

CLONE FROM GITHUB:
git clone git@github.com:/<user>/<project> — Download repo (later you keep refreshing with 'git pull origin master') -> You need SSH key. If you don't want, use https://github.com/<user>/<repo> for address.


GENERATE SSH KEY:
1. — Check for existing keys: cd ~/.ssh; ls -al
2. — Generate new key: ssh-keygen -t rsa -C "your_email@example.com"
3. — Add your key to the ssh-agent: ssh-add ~/.ssh/id_rsa
4. — Add your key to GitHub: copy contents of ~/.ssh/id_rsa.pub and paste them into key field at 'Account settings' > 'SSH Keys' > 'Add SSH key'.


ADD TO GITHUB:
```
# Create remote repository on website.
git remote add origin git@github.com:/<user>/<project>.git
git pull origin master
git push origin master
# Sometimes also: git push --set-upstream origin master
```

REMOTE:
git remote  update — Get info about state of remote
    show origin — Print address of the origin
    set-url origin <origin> — `git@github.com:<user>/<repo>.git` - Change the url of origin, ssh key needed; `https://www.github.com/<user>/<repo>.git` - Same, but withouth key.
git status -uno — Check if everything up-to-date
git fetch; git checkout <branch> — Checkout remote branch


TAGS:
git push --tags — Push tags
git fetch --tags — Pulling tags (automatically if on the same branch and there is a new commit?)


UNDO:
git reset  --hard HEAD~1 — Delete last commit and all of its changes
    HEAD~1 — Delete last commit but keep your changes


ALSO USEFUL:
git checkout HEAD^ <file> — Retrieve deleted file
git rm --cached <file> — Untrack file without deleting it
git tag -a 0.9.1 -m "Version 0.9.1 release" — Tag latest commit
git tag — List local tags
chown -R <user>:<group> * (sudo) — In .git/objects 
git format-patch -1 <sha> — Generate patch file
git rev-parse HEAD — Get sha of head
git revert — 
git describe — Print version and hash of HEAD
git log --name-only --author=<name> — Print changed files by commit
git log <file> — Print files history
git ls-files — List files
git show <revision>:<file> — Take a peek at the older revision of the file
git diff <commit> <commit> — Compare two commits
git stash — If you want to switch branches, but you don't want to commit your changes yet, you can 'stash' them
git stash apply — Apply the changes you stashed
git stash list — List all the stashes
git stash show -p stash@{0} — Show the diff of most recent stash
git update-index --chmod=+x <file> — Change files permissions
git config -l — Print repos configuration settings
git config core.filemode false — Ignores executable bit of the files


CHECKOUT:
git log > ../gitLog — First save log to file
git checkout <hash> — Then checkout previous versions
git checkout head — Return to head


GITHUB MD FORMAT:
![Alt text](/doc/basket-stats.png?raw=true "<Description>") — Insert image


BISECT:
git bisect start — 
git bisect bad — Tell git that current version is bad
git bisect good v25.0.2 — Tell git the last good version you know about.
    Now git will checkout a version in between, so you can check it and tell:
git bisect bad/good — This will continue until the commit that introduced the bug is found 
git bisect reset — Exit bisect mode


TOOLS:
gitk — Repo explorer
gitg — A bit nicer version
tig — Text based repo explorer
gitstats — Generates stats for git repo, outputs HTML


VIRTUAL BOX:
git config core.filemode false — Ignores the filemode changes made by the host system
git config --global --unset https.proxy — If problem pulling



###########
##  VIM  ##
###########

+<linenum> — Open file at line number
alt+<normal mode key> — Escape, key !!!!!!!!!!!!!!!!!
ctrl+[ — Escape
. — Execute last command again
; — Repeat the last character-wise search
\c — Case insensitive search
? — Search backward
V — Linewise visual mode
~ — Switch case
> — Tab selection right 
>> — Tab line right
P — Paste before cursor
x — Delete character
gF — Open file under cursor
K — Look up word under cursor in man pages
ctrl+v — Select visual box (block select)
:e — Reload file
:sav — Save file as and keep new file open (save as)


HELP:
ctrl+] — Follow link
ctrl+o — Go back
:q — Exit help  


MOVEMENT:
e — End of word
E — End of WORD
W — Start of WORD
ge — End of previous word
), ( — Sentence
{, } — Paragraph
]], [[ — Section
:<num> — Goto line number
ctrl+o — Go to previous location
ctrl+i — Go to next location
% — Jump to matching bracket


LINES:
0 — Start of line
^,_ — First non-blank of line
+,- — First non-blank of next/previous line
Enter — First non-blank of next line


SCREEN LINES:
g0, g$ — Start/end of screen line
gm — Middle of screen line
gk, gj — Up/down one screen line


PAGE UP/DOWN:
H,M,L — Go to top/middle/bottom of screen
ctrl F,B — Page up/down
ctrl D,U — Half page up/down
ctrl E,Y — One more line at bottom/top 
z Enter, z., z- — Reposition line with cursor at top/middle/bottom


SEARCH:
*,# — Search forward/backward for exact word under cursor
g*,g# — Same, but even when word is embedded
% — Find match of current brace, quote,...
fx,Fx — Move cursor forward/backward to x on current line
tx,Tx — Same, but to one char before x
;/, — Repeat/reverse last
:%s/old/new/gc — Replace, like sed, c means with conformations


MARKS:
'" — Move to position of last edit of file
`. — Move to last change in file
`0 — Position where you last exited vim


INSERT MODE COMMANDS:
ctrl+h — Backspace
ctrl+u — Delete line
ctrl+w — Delete previous word


MACROS:
q<x> — Record actions (macro) into x
q — Stop recording macro
@<x> — Execute x (macro)


REGISTERS:
"ayy — Copy line into register a
"ap — Paste register a
:reg — Access all registers


SET COMMAND:
:set <x> — Set x
:set no<x>, <x>! — Unset x
:set <x>=value — Assign x
:set <x>-=value — Remove value form <x>
:set all — Print all values
:set <x>? — Print x 


SET COMMAND OPERANDS:
autoident, ai — Autoident (noai)
backup, bk  — Back file up before overwrite (nobackup) 
ignorecase, ic — Ignore case in search (noic)
number, nu — Display line numbers (nonu)
relativenumber, rnu — Display relative numbers (nornu)
shiftwidth, sw — Number of spaces added when indenting (8)
tabstop, ts — Tab width (8)
wrap — Wrap lines (wrap)
wrapscan, ws — Search wraps around file (ws)
mouse=a — Mouse mode (use shift when selecting to copy to clipboard)
linebreak — Do not break words

:set iskeyword-=. — Remove dot from words part (two words if separated with dot)


EDIT COMMANDS:
[n] operation [m] motion — If both n and m are specified then n x m

c, d, y — Change, delete, yank 
C, D, Y — Till the end of line
cc, dd, yy — Current line
cf<x>, df<x>, yf<x> — Forward up to x
c), d), y) — Sentence

~ — Change case of character
g~w — Switch case of a word
gu, gU — To lower/upper case

[p — Paste but match current indentation
r — Replace character
S — Substitute entire line
x,X — Delete character/delete back
. — Repeat last change
ctrl+a, ctrl+x — Increment/decrement number under cursor


AUTOMATIC LINEBRAKE (WRAP):
gq — Formats (wraps) selected text 
gqq — Format current line
:set tw=72 — Set text width
ADVANCED:
tw=72 fo=cq wm=0 — No automatic wrapping, rewrapping will wrap to 72
tw — Controls the wrap width you would like to use
fo — Controls whether or not automatic text wrapping is enabled, depending whether or not the t flag is set
wm — Controls when to wrap based on terminal size


COLORSCHEME:
:colorscheme — darkblue, torte — Nice, darker
    slate, default — Less contrast
:highlight Normal ctermbg=grey — Set light background


SPELLCHECK:
:set spell spelllang=en_us — Turn spellcheck on
:set nospell — Turn off
:setlocal spell spelllang=en_us — Set dictionary
z= — Show suggestions for misspelled word
]s — Go to next misspelled word
[s — Go to previous misspelled word


TABS:
:tabe <file> — Open new tab
gt, gT — Go to next/previous tab
ctrl+pgup/pgdn — Switch tab
vim -p — Open one tab page per file
ZZ — Save and close tab (same as :wq)


SPLITS:
:vsp — Split vertically
ctrl-w, direction — Move to split


AUTOCOMPLETE:
ctrl+n — Show autocomplete suggestions


HEXDUMP:
:%!xxd — Convert to hex
:%!xxd -r — Convert back


VUNDLE:
:PluginInstall — Install plugins


REFORMAT CODE:
= — Fix indentation



##########
## MISC ##
##########

PIRATEBAY:
torrents.thepiratebay.sx/7532474/Cabin.torrent — Download torrent file


JAVA:
javac -cp <path>:<path>... — Tell Java where libraries are located
java -Xmx6g myprogram — Reserve 6 giga for process
    -jar <jar> — Execute jar
    -cp .:<path>:<path>... — Tell java where libraries are located, you also need to pass the location of class among paths, hence .:
export _JAVA_OPTIONS=-Xmx1000m — Set heap space globally
appletviewer <page>.html — Run Java applet
jps -lvm — List java processes
jmap -histo:live <pid> — Memory map
jvisualvm — Profiler
jar cvfe "bla.jar" <main_class> *.class — Create executable jar
jar xf <jar> — Extract files from jar
jar tf <jar> — Print contents of a jar 


INSTALL ORACLE JDK:
```
sudo apt-get remove openjdk*
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer
```

INSTALL ORACLE JDK ON DEBIAN:
```
echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | sudo tee /etc/apt/sources.list.d/webupd8team-java.list
echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | sudo tee -a /etc/apt/sources.list.d/webupd8team-java.list
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886
sudo apt-get update
sudo apt-get install oracle-java7-installer
sudo apt-get install oracle-java7-set-default
```

FIREFOX:
about:config — Layout.css.devPixelsPerPx default zoom (-1.0)


XRANDR:
xrandr  --output VGA1 --primary — Changes primary screen 
    --output VGA1 --auto --pos 0x0  — `--output LVDS1 --auto --right-of VGA1` - To change their relative positions
    -q — List devices
    --auto — Reset
    --output LVDS1 --off — Turn off laptop screen
    --output [VGA|HDMI] --mode 1600x1200 — 24" 16x12 on


MOUNT ISO:
```
sudo mkdir /media/x
sudo mount -o loop <path_to_iso> /media/x
```

ECLIPSE:
ctrl+1 — Quick fix
alt+shift+s — Source submenu
ctrl+F7, esc — Close pop-up console window
ctrl+7, ctrl+/ — Toggle comment
F3 — Goto definition
objectaid — UML plugin 


WINE:
winecfg — Drives tab to set drive
wine explorer /desktop=abalaba,1024x768 app.exe — Run wine app in virtual desktop
reason on wine: down alt down — Open menu
regedit — Registry editor


CYGWIN:
[cygwin] ssh-host-cofig —  
[command prompt] net start sshd — 
[any] ssh <windows_username - CASE MATTERS!>@<host> — Run sshd (use windows password)


GOLANG:
go  build       — Compile packages and dependencies
    clean       — Remove object files
    env         — Print Go environment information
    fix         — Run go tool fix on packages
    fmt         — Run gofmt on package sources
    get         — Download and install packages and dependencies (first you need to set GOPATH to dir where packages will get downloaded)
    install     — Compile and install packages and dependencies
    list        — List packages
    run         — Compile and run Go program
    test        — Test packages
    tool        — Run specified go tool
    version     — Print Go version
    vet         — Run go tool vet on packages

syntax highlight — `https://github.com/jnwhiteh/vim-golang`
for gedit — `sudo cp /usr/share/gtksourceview-3.0/language-specs/go.lang /usr/share/gtksourceview-2.0/language-specs/`
simple ncurses — Go get github.com/nsf/termbox-go


REPACKAGING A LINUX INSTALL ISO:
```
# Mount ISO
mkdir -p /mnt/linux
mount -o loop /tmp/linux-install.iso /mnt/linux
```

```
# Copy contents to a working directory
cd /mnt/
tar -cvf — Linux | (cd /var/tmp && tar -xf — )
```

```
# Make your changes and repackage (on Debian use genisoimage). -c passes the name of the file that will be created
cd /var/tmp/linux
mkisofs -o ../your-new.iso -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -J -R -V Your Disk Name Here .
```

GDB:
gdb <cmd> — Start gdb
run <arguments>  — Start debugging
run < <file> — Run with piped input
up — Follow trace
print <variable> — Print variable


COREDUMP:
ulimit -c unlimited — Set core file limit to unlimited
gdb <cmd> core — Debug core file with gdb


CHROME:
F6, ctrl+l, alt+d — Go to address bar