Bach color Linux

# Reset
Color_Off='\033[0m'       # Text Reset

# Regular Colors
Black='\033[0;30m'        # Black
Red='\033[0;31m'          # Red
Green='\033[0;32m'        # Green
Yellow='\033[0;33m'       # Yellow
Blue='\033[0;34m'         # Blue
Purple='\033[0;35m'       # Purple
Cyan='\033[0;36m'         # Cyan
White='\033[0;37m'        # White

# Bold
BBlack='\033[1;30m'       # Black
BRed='\033[1;31m'         # Red
BGreen='\033[1;32m'       # Green
BYellow='\033[1;33m'      # Yellow
BBlue='\033[1;34m'        # Blue
BPurple='\033[1;35m'      # Purple
BCyan='\033[1;36m'        # Cyan
BWhite='\033[1;37m'       # White

# Underline
UBlack='\033[4;30m'       # Black
URed='\033[4;31m'         # Red
UGreen='\033[4;32m'       # Green
UYellow='\033[4;33m'      # Yellow
UBlue='\033[4;34m'        # Blue
UPurple='\033[4;35m'      # Purple
UCyan='\033[4;36m'        # Cyan
UWhite='\033[4;37m'       # White

# Background
On_Black='\033[40m'       # Black
On_Red='\033[41m'         # Red
On_Green='\033[42m'       # Green
On_Yellow='\033[43m'      # Yellow
On_Blue='\033[44m'        # Blue
On_Purple='\033[45m'      # Purple
On_Cyan='\033[46m'        # Cyan
On_White='\033[47m'       # White

# High Intensity
IBlack='\033[0;90m'       # Black
IRed='\033[0;91m'         # Red
IGreen='\033[0;92m'       # Green
IYellow='\033[0;93m'      # Yellow
IBlue='\033[0;94m'        # Blue
IPurple='\033[0;95m'      # Purple
ICyan='\033[0;96m'        # Cyan
IWhite='\033[0;97m'       # White

# Bold High Intensity
BIBlack='\033[1;90m'      # Black
BIRed='\033[1;91m'        # Red
BIGreen='\033[1;92m'      # Green
BIYellow='\033[1;93m'     # Yellow
BIBlue='\033[1;94m'       # Blue
BIPurple='\033[1;95m'     # Purple
BICyan='\033[1;96m'       # Cyan
BIWhite='\033[1;97m'      # White

# High Intensity backgrounds
On_IBlack='\033[0;100m'   # Black
On_IRed='\033[0;101m'     # Red
On_IGreen='\033[0;102m'   # Green
On_IYellow='\033[0;103m'  # Yellow
On_IBlue='\033[0;104m'    # Blue
On_IPurple='\033[0;105m'  # Purple
On_ICyan='\033[0;106m'    # Cyan
On_IWhite='\033[0;107m'   # White

the escape character in bashhex and octal respectively:

|       | bash  | hex    | octal   | NOTE                         |
|-------+-------+--------+---------+------------------------------|
| start | \e    | \x1b   | \033    |                              |
| start | \E    | \x1B   | -       | x cannot be capital          |
| end   | \e[0m | \x1m0m | \033[0m |                              |
| end   | \e[m  | \x1b[m | \033[m  | 0 is appended if you omit it |
|       |       |        |         |                              |

short example:

| color       | bash         | hex            | octal          | NOTE                                  |
|-------------+--------------+----------------+----------------+---------------------------------------|
| start green | \e[32m<text> | \x1b[32m<text> | \033[32m<text> | m is NOT optional                     |
| reset       | <text>\e[0m  | <text>\1xb[0m  | <text>\033[om  | o is optional (do it as best practice |
|             |              |                |                |                                       |

bash exception:

If you are going to use these codes in your special bash variables

  • PS0
  • PS1
  • PS2 (= this is for prompting)
  • PS4

you should add extra escape characters so that  can interpret them correctly. Without this adding extra escape characters it works but you will face problems when you use Ctrl + r for search in your history.

exception rule for bash

You should add \[ before any starting ANSI code and add \] after any ending ones.
Example:
in regular usage: \033[32mThis is in green\033[0m
for PS0/1/2/4: \[\033[32m\]This is in green\[\033[m\]

\[ is for start of a sequence of non-printable characters
\] is for end of a sequence of non-printable characters

Tip: for memorize it you can first add \[\] and then put your ANSI code between them:
– \[start-ANSI-code\]
– \[end-ANSI-code\]

type of color sequence:

  1. 3/4 bit
  2. 8 bit
  3. 24 bit

Before diving into these colors, you should know about 4 modes with these codes:

1. color-mode

It modifies the style of color NOT text. For example make the color bright or darker.

  • 0 reset
  • 1; lighter than normal
  • 2; darker than normal

This mode is not supported widely. It is fully support on Gnome-Terminal.

2. text-mode

This mode is for modifying the style of text NOT color.

  • 3; italic
  • 4; underline
  • 5; blinking (slow)
  • 6; blinking (fast)
  • 7; reverse
  • 8; hide
  • 9; cross-out

and are almost supported.
For example KDE-Konsole supports 5; but Gnome-Terminal does not and Gnome supports 8;but KDE does not.

3. foreground mode

This mode is for colorizing the foreground.

4. background mode

This mode is for colorizing the background.

The below table shows a summary of 3/4 bit version of ANSI-color

|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
| color-mode | octal    | hex     | bash  | description      | example (= in octal)         | NOTE                                 |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
|          0 | \033[0m  | \x1b[0m | \e[0m | reset any affect | echo -e "\033[0m"            | 0m equals to m                       |
|          1 | \033[1m  |         |       | light (= bright) | echo -e "\033[1m####\033[m"  | -                                    |
|          2 | \033[2m  |         |       | dark (= fade)    | echo -e "\033[2m####\033[m"  | -                                    |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
|  text-mode | ~        |         |       | ~                | ~                            | ~                                    |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
|          3 | \033[3m  |         |       | italic           | echo -e "\033[3m####\033[m"  |                                      |
|          4 | \033[4m  |         |       | underline        | echo -e "\033[4m####\033[m"  |                                      |
|          5 | \033[5m  |         |       | blink (slow)     | echo -e "\033[3m####\033[m"  |                                      |
|          6 | \033[6m  |         |       | blink (fast)     | ?                            | not wildly support                   |
|          7 | \003[7m  |         |       | reverse          | echo -e "\033[7m####\033[m"  | it affects the background/foreground |
|          8 | \033[8m  |         |       | hide             | echo -e "\033[8m####\033[m"  | it affects the background/foreground |
|          9 | \033[9m  |         |       | cross            | echo -e "\033[9m####\033[m"  |                                      |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
| foreground | ~        |         |       | ~                | ~                            | ~                                    |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
|         30 | \033[30m |         |       | black            | echo -e "\033[30m####\033[m" |                                      |
|         31 | \033[31m |         |       | red              | echo -e "\033[31m####\033[m" |                                      |
|         32 | \033[32m |         |       | green            | echo -e "\033[32m####\033[m" |                                      |
|         33 | \033[32m |         |       | yellow           | echo -e "\033[33m####\033[m" |                                      |
|         34 | \033[32m |         |       | blue             | echo -e "\033[34m####\033[m" |                                      |
|         35 | \033[32m |         |       | purple           | echo -e "\033[35m####\033[m" | real name: magenta = reddish-purple  |
|         36 | \033[32m |         |       | cyan             | echo -e "\033[36m####\033[m" |                                      |
|         37 | \033[32m |         |       | white            | echo -e "\033[37m####\033[m" |                                      |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
|         38 | 8/24     |                    This is for special use of 8-bit or 24-bit                                            |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
| background | ~        |         |       | ~                | ~                            | ~                                    |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
|         40 | \033[40m |         |       | black            | echo -e "\033[40m####\033[m" |                                      |
|         41 | \033[41m |         |       | red              | echo -e "\033[41m####\033[m" |                                      |
|         42 | \033[42m |         |       | green            | echo -e "\033[42m####\033[m" |                                      |
|         43 | \033[43m |         |       | yellow           | echo -e "\033[43m####\033[m" |                                      |
|         44 | \033[44m |         |       | blue             | echo -e "\033[44m####\033[m" |                                      |
|         45 | \033[45m |         |       | purple           | echo -e "\033[45m####\033[m" | real name: magenta = reddish-purple  |
|         46 | \033[46m |         |       | cyan             | echo -e "\033[46m####\033[m" |                                      |
|         47 | \033[47m |         |       | white            | echo -e "\033[47m####\033[m" |                                      |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|
|         48 | 8/24     |                    This is for special use of 8-bit or 24-bit                                            |                                                                                       |
|------------+----------+---------+-------+------------------+------------------------------+--------------------------------------|

The below table shows a summary of 8 bit version of ANSI-color

|------------+-----------+-----------+---------+------------------+------------------------------------+-------------------------|
| foreground | octal     | hex       | bash    | description      | example                            | NOTE                    |
|------------+-----------+-----------+---------+------------------+------------------------------------+-------------------------|
|        0-7 | \033[38;5 | \x1b[38;5 | \e[38;5 | standard. normal | echo -e '\033[38;5;1m####\033[m'   |                         |
|       8-15 |           |           |         | standard. light  | echo -e '\033[38;5;9m####\033[m'   |                         |
|     16-231 |           |           |         | more resolution  | echo -e '\033[38;5;45m####\033[m'  | has no specific pattern |
|    232-255 |           |           |         |                  | echo -e '\033[38;5;242m####\033[m' | from black to white     |
|------------+-----------+-----------+---------+------------------+------------------------------------+-------------------------|
| foreground | octal     | hex       | bash    | description      | example                            | NOTE                    |
|------------+-----------+-----------+---------+------------------+------------------------------------+-------------------------|
|        0-7 |           |           |         | standard. normal | echo -e '\033[48;5;1m####\033[m'   |                         |
|       8-15 |           |           |         | standard. light  | echo -e '\033[48;5;9m####\033[m'   |                         |
|     16-231 |           |           |         | more resolution  | echo -e '\033[48;5;45m####\033[m'  |                         |
|    232-255 |           |           |         |                  | echo -e '\033[48;5;242m####\033[m' | from black to white     |
|------------+-----------+-----------+---------+------------------+------------------------------------+-------------------------|

The 8-bit fast test:
for code in {0..255}; do echo -e "\e[38;05;${code}m $code: Test"; done

The below table shows a summary of 24 bit version of ANSI-color

|------------+-----------+-----------+---------+-------------+------------------------------------------+-----------------|
| foreground | octal     | hex       | bash    | description | example                                  | NOTE            |
|------------+-----------+-----------+---------+-------------+------------------------------------------+-----------------|
|      0-255 | \033[38;2 | \x1b[38;2 | \e[38;2 | R = red     | echo -e '\033[38;2;255;0;02m####\033[m'  | R=255, G=0, B=0 |
|      0-255 | \033[38;2 | \x1b[38;2 | \e[38;2 | G = green   | echo -e '\033[38;2;;0;255;02m####\033[m' | R=0, G=255, B=0 |
|      0-255 | \033[38;2 | \x1b[38;2 | \e[38;2 | B = blue    | echo -e '\033[38;2;0;0;2552m####\033[m'  | R=0, G=0, B=255 |
|------------+-----------+-----------+---------+-------------+------------------------------------------+-----------------|
| background | octal     | hex       | bash    | description | example                                  | NOTE            |
|------------+-----------+-----------+---------+-------------+------------------------------------------+-----------------|
|      0-255 | \033[48;2 | \x1b[48;2 | \e[48;2 | R = red     | echo -e '\033[48;2;255;0;02m####\033[m'  | R=255, G=0, B=0 |
|      0-255 | \033[48;2 | \x1b[48;2 | \e[48;2 | G = green   | echo -e '\033[48;2;;0;255;02m####\033[m' | R=0, G=255, B=0 |
|      0-255 | \033[48;2 | \x1b[48;2 | \e[48;2 | B = blue    | echo -e '\033[48;2;0;0;2552m####\033[m'  | R=0, G=0, B=255 |
|------------+-----------+-----------+---------+-------------+------------------------------------------+-----------------|

some screen-shots

foreground 8-bit summary in a .gif

foreground.gif

background 8-bit summary in a .gif

background.gif

color summary with their values

enter image description here enter image description here enter image description here enter image description here

blinking on KDE-Terminal

KDE-blinking

 a simple C code that shows you more

cecho_screenshot

 a more advanced tool that I developed to deal with these colors:
bline


color-mode shot

fade-normal-bright

text mode shot

only-text-mode

combining is OK

combine

more shots

Tips and Tricks for Advanced Users and Programmers:

Can we use these codes in a programming language?

Yes, you can. I experienced in  

Are they slow down the speed of a program?

I think, NO.

Can we use these on Windows?

3/4-bit Yes, if you compile the code with gcc
some screen-shots on Win-7

How to calculate the length of code?

\033[ = 2, other parts 1

Where can we use these codes?

Anywhere that has a tty interpreter
xtermgnome-terminalkde-terminalmysql-client-CLI and so on.
For example if you want to colorize your output with mysql you can use Perl

#!/usr/bin/perl -n
print "\033[1m\033[31m$1\033[36m$2\033[32m$3\033[33m$4\033[m" while /([|+-]+)|([0-9]+)|([a-zA-Z_]+)|([^\w])/g;

store this code in a file name: pcc (= Perl Colorize Character) and then put the file a in valid PATHthen use it anywhere you like.

ls | pcc
df | pcc

inside mysql first register it for pager and then try:

[user2:db2] pager pcc
PAGER set to 'pcc'
[user2:db2] select * from table-name;

pcc

It does NOT handle Unicode.

Do these codes only do colorizing?

No, they can do a lot of interesting things. Try:

echo -e '\033[2K'  # clear the screen and do not move the position

or:

echo -e '\033[2J\033[u' # clear the screen and reset the position

There are a lot of beginners that want to clear the screen with system( "clear" ) so you can use this instead of system(3) call

Are they available in Unicode?

Yes. \u001b

Which version of these colors is preferable?

It is easy to use 3/4-bit, but it is much accurate and beautiful to use 24-bit.
If you do not have experience with  so here is a quick tutorial:
24 bits means: 00000000 and 00000000 and 00000000. Each 8-bit is for a specific color.
24..17 is for  and 16..9 for  and 8..1 for 
So in  #FF0000 means  and here it is: 255;0;0
in  #00FF00 means  which here is: 0;255;0
Does that make sense? what color you want combine it with these three 8-bit values.

reference:
Wikipedia
ANSI escape sequences
tldp.org
tldp.org
misc.flogisoft.com
some blogs/web-pages that I do not remember

Running Tomcat Automatically At Linux Startup

A potential drawback of installing Tomcat from a binary distribution instead of using a Linux-packaged version is that you’ll have to do some extra legwork to make Tomcat start automatically when Linux boots up.  To make this process easy and pain-free, follow this simple guide.

Step 1 – Create A Tomcat-Specific User and User Group

It’s a bad idea to run Tomcat as the root user, especially if you’re going to be starting Tomcat automatically.  It’s much more secure to create a new group and user specifically to run Tomcat.  You can do so with the following commands (in this example, we have created a user group named tomcat, and a user named tomcat with the password tomcat; you can certainly be more creative if you wish):

$ groupadd tomcat
$ useradd -s /sbin/nologin -g tomcat -d /path/to/tomcat tomcat

or
$ useradd -r -s /sbin/nologin tomcat

-r for system user
$ passwd tomcat

-r, –system
Create a system account.

System users will be created with no aging information in /etc/shadow, and their
numeric identifiers are chosen in the SYS_UID_MIN-SYS_UID_MAX range, defined in
/etc/login.defs, instead of UID_MIN-UID_MAX (and their GID counterparts for the
creation of groups).

Note that useradd will not create a home directory for such an user, regardless
of the default setting in /etc/login.defs (CREATE_HOME). You have to specify the
-m options if you want a home directory for a system account to be created.

-s, –shell SHELL
The name of the user’s login shell. The default is to leave this field blank,
which causes the system to select the default login shell specified by the SHELL
variable in /etc/default/useradd, or an empty string by default.

Esample:

useradd -m -d /home/thenewuser -s /bin/bash -c "the new user" -U thenewuser

-c “message” : extra information about the user.

-U thenewuser : Create a group with the same name as the user, and add the user to this group.

-N : the -N argument tells the system not to create a group having the user’s name

-m, –create-home are same: Create the user’s home directory if it does not exist.

-d, –home HOME_DIR : The new user will be created using HOME_DIR as the value for the user’s login directory.
if -d is not used the default homedirectory will be /home/thenewuser

-m -d /data/thenewuser : the -m argument creates the /data/thenewuser homedirectory, specified by the -d argument.

-M : the -M argument tells the system not to create a home directory

-s /bin/bash : the -s is used for specifing the user’s default shell, /bin/bash in this case.

-s or –shell are same.

-s /sbin/nologin : The /sbin/nologin for Fedora and /usr/sbin/nologin for Debian are two shells that return you a polite message like “this account is not available” and do not allow you to log into the system. This message can be customized.

-s /bin/false : Is an old shell used to deny a user’s login. The /bin/false exits immediatly when false exists. The user accounts with /bin/false or /bin/true as their default shells are locked.

-s /sbin/nologin belongs to unix-linux while /bin/false part of GNU Coreutils. These shells must be listed in the /etc/shells file, to work.

The users with /sbin/nologin (or /usr/sbin/nologin) can connect through ssh or ftp, but the users with /bin/false are completely locked out from the system.

with useradd -D : You can also view the default parameters set for new user to be created using

# useradd -D
GROUP=100
HOME=/home
INACTIVE=-1
EXPIRE=
SHELL=/bin/bash
SKEL=/etc/skel
CREATE_MAIL_SPOOL=yes
#

Step 2 – Adjust Ownership For New Users And Groups

Now that you have created a user to run Tomcat, you’ll need to give them access to the correct directories.  Use the following commands, substituting your own usernames and groups as necessary:

# chown -R tomcat.tomcat /path/to/tomcat
# chmod 775 /path/to/tomcat/webapps
The first gives ownership of the Tomcat directories to the Tomcat user, and the second gives the user write access for the webapps directory.

Step 3 – Relay Traffic For Non-Root Tomcat User

When running Tomcat as a user other than the root user, you will not be able to bind to port 80, which is where Tomcat listens for HTTP requests.  To get around this, you can use Netfilter, which is packaged with all major Linux distributions:

# iptables -t nat -I PREROUTING -p tcp –dport 80 -j REDIRECT –to-ports 8080
# iptables -t nat -I OUTPUT -p tcp –dport 80 -j REDIRECT –to-ports 8080
To preserve these rules through re-boot, save them with the “ip-tables-save” command, and then follow the procedure appropriate for your Linux distribution (for most distributions, this means editing the iptables init script; Debian users should load the configuration via a script called by if-up.d or pre-up.d).

Step 3 – Create A Custom init Script

To start Tomcat at Linux boot time, we’ll need to create an init script that calls the startup.sh and shutdown.sh scripts included with Tomcat.

The actual creation of this script is outside the scope of this article, but there are many useful resources available online.  All you need to know in order to use the basic init script format to call Tomcat is how the startup.sh and shutdown.sh scripts work.

For more information about these scripts, visit our Tomcat Start page, which includes a simple, step-by-step guide to Tomcat’s three start-up shell scripts.

like :

chmod 774 /opt/apache-tomcat-8.0.12-1/ -Rf

export JAVA_OPTS=”-agentlib:hprof=cpu=samples,file=/var/log/cpuTest.log”

#/opt/apache-tomcat-8.0.12-2/bin/startup.sh
TOMCAT_OWNER=tomcat;
export TOMCAT_OWNER

CATALINA_HOME=/opt/apache-tomcat-8.0.12-2;
export CATALINA_HOME

/bin/su -s /bin/bash $TOMCAT_OWNER -c $CATALINA_HOME/bin/startup.sh

 

 

 

How to find process listening over a port

List all tcp ports using netstat -at

netstat -at
 netstat -ltnp 

-p means list all the programs run over the port

List all udp ports using netstat -au

netstat -aup

List only listening ports using netstat -l

netstat -lp

List only the listening UNIX Ports using netstat -lx

netstat -lxp

lsof command (LiSt Open Files) is used to list all open files on a Linux system. To install it on your system, type the command below.

$ sudo yum install lsof	        #RHEL/CentOS 
$ sudo apt install lsof		#Debian/Ubuntu
$ sudo dnf install lsof		#Fedora 22+

To find the process/service listening on a particular port, type (specify the port).

$ lsof -i :80