Changing colour of text and background of terminal?

I can change the colour through preference , but how can I change the background colour and text colour of terminal through the command line?

On certain XTerm/ANSI-compatible terminals (like xterm and gnome-terminal), you can set colors using a palette bigger then the default 8/16-colors palette (for example using an 88-colors, 256-colors or 16777216-colors (RGB) palette; both xterm and gnome-terminal support both the 256-colors and the 16777216-colors (RGB) palette); mind that the shell might override this (this is the case e.g. for zsh).

Here's a script to list the colors in the 256-color palette along with their ANSI color code in XTerm/ANSI-compatible terminals with a 256-color palette support:

#!/bin/bash
for((i=16; i<256; i++)); do
    printf "\e[48;5;${i}m%03d" $i;
    printf '\e[0m';
    [ ! $((($i - 15) % 6)) -eq 0 ] && printf ' ' || printf '\n'
done

Depending on whether you want to apply the color to the foreground or to the background, use an <fg_bg> value of 38 or 48 (respectively) in the following command:

printf '\e[<fg_bg>;5;<ANSI_color_code>m'

For example, to set the foreground color (<fg_bg>=38) to red (<ANSI_color_code>=196) and the background color (<fg_bg>=48) to black (<ANSI_color_code>=0):

printf '\e[38;5;196m Foreground color: red\n'
printf '\e[48;5;0m Background color: black\n'

It's necessary to redraw the prompt using printf '\e[K' in order for the background color to apply to the whole line and in order for the foreground color to apply to the cursor:

The same thing can be accomplished using RGB values instead of ANSI color codes in a compatible terminal; depending on whether you want to apply the color to the foreground or to the background, use an <fg_bg> value of 38 or 48 (respectively) in the following command:

printf '\e[<fg_bg>;2;<R>;<G>;<B>m'

For example, to set the foreground color (<fg_bg>=38) to red (<R>=255, <G>=0, <B>=0) and the background color (<fg_bg>=48) to black (<R>=0, <G>=0, <B>=0):

printf '\e[38;2;255;0;0m Foreground color: red\n'
printf '\e[48;2;0;0;0m Background color: black\n'

Again, it's necessary to redraw the prompt using printf '\e[K' in order for the background color to apply to the whole line and in order for the foreground color to apply to the cursor:

Using either methods, you can use printf '\e[0m' to reset all the attributes:

Information as found on this page, excluding preview column:

Sequences are composed of the Escape character (often represented by ”^[” or ”<Esc>”) followed by some other characters: ”^[FCm” (where FC is one of the numbers in the bulleted list below).

In bash, the Esc code can be either of the following:

1. \e
2. \033 (octal)
3. \x1B (hexadecimal)

Note 1: The "\e[0m" sequence removes all attributes (formatting and colors). It can be a good idea to add it at the end of each colored text.

Note 2: Foreground and background colours may vary, depending on the terminal's configuration and not all colours are supported.

Set/Reset

• 0: Reset/remove all modifier, foreground and background attributes: echo -e "\e[0mNormal Text"
• 1: Bold/Bright: echo -e "Normal \e[1mBold"
• 2: Dim: echo -e "Normal \e[2mDim"
• 4: Underlined: echo -e "Normal \e[4mUnderlined"
• 5: Blink (doesn't work in most terminals except XTerm): echo -e "Normal \e[5mBlink"
• 7: Reverse/Invert: echo -e "Normal \e[7minverted"
• 8: Hidden (useful for sensitive info): echo -e "Normal \e[8mHidden Input"
• 21: Reset/Remove bold/bright: echo -e "Normal \e[1mBold \e[21mNormal"
• 22: Reset/Remove dim: echo -e "Normal \e[2mDim \e[22mNormal"
• 24: Reset/Remove underline: echo -e "Normal \e[4mUnderlined \e[24mNormal"
• 25: Reset/Remove blink: echo -e "Normal \e[5mBlink \e[25mNormal"
• 27: Reset/Remove reverse/invert: echo -e "Normal \e[7minverted \e[27mNormal"
• 28: Reset/Remove hidden: echo -e "Normal \e[8mHidden \e[28mNormal"

Foreground

• 39: Default (usually green, white or light gray): echo -e "Default \e[39mDefault"
• 30: Black: echo -e "Default \e[30mBlack" (best combined with a background colour: echo -e "Default \e[30;107mBlack on white")
• 31: Red (don't use with green background)
• 32: Green
• 33: Yellow
• 34: Blue
• 35: Magenta/Purple
• 36: Cyan
• 37: Light Gray
• 90: Dark Gray
• 91: Light Red
• 92: Light Green
• 93: Light Yellow
• 94: Light Blue
• 95: Light Magenta/Pink
• 96: Light Cyan
• 97: White

Background

• 49: Default background color (usually black or blue)
• 40: Black
• 41: Red
• 42: Green
• 43: Yellow
• 44: Blue
• 45: Magenta/Purple
• 46: Cyan
• 47: Light Gray (don't use with white foreground)
• 100: Dark Gray (don't use with black foreground)
• 101: Light Red
• 102: Light Green (don't use with white foreground)
• 103: Light Yellow (don't use with white foreground)
• 104: Light Blue (don't use with light yellow foreground)
• 105: Light Magenta/Pink (don't use with light foreground)
• 106: Light Cyan (don't use with white foreground)
• 107: White (don't use with light foreground)

To set both the foreground and background colours at once, use ther form echo -e "\e[S;FG;BGm". For example: echo -e "\e[1;97;41m" (bold white foreground on red background)

For 256 colour options, see the source page.