Custom Bash Prompt

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#--------------------Custom bash prompt----------------------
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# you can copy all these lines directly to .bashrc but I recommend to
# make a script file and call it from .bashrc like the below line
# source ~/.my-scripts/bash-prompt.sh

#colors
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# foreground   background   color
# 30 - - - - - 40 - - - - - # black
# 31 - - - - - 41 - - - - - # red
# 32 - - - - - 42 - - - - - # green
# 33 - - - - - 43 - - - - - # yellow
# 34 - - - - - 44 - - - - - # blue
# 35 - - - - - 45 - - - - - # magenta
# 36 - - - - - 46 - - - - - # cyan
# 37 - - - - - 47 - - - - - # white

# 00 - - - - - # dark
# 01 - - - - - # light


# special characters
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# \a : an ASCII bell character (07)
# \d : the date in "Weekday Month Date" format (e.g., "Tue May 26")
# \D : \D{format}       the format is passed to strftime(3) and the result is
#      inserted into the prompt string; an empty format results in a
#      locale-specific time representation. The braces are required
# \e : an ASCII escape character (033)
# \h : the host name up to the first '.'
# \H : the host name
# \j : the number of jobs currently managed by the shell
# \l : the base name of the shell’s terminal device name
# \n : newline
# \r : carriage return
# \s : the name of the shell, the base name of $0 (the portion following the final slash)
# \t : the current time in 24-hour HH:MM:SS format
# \T : the current time in 12-hour HH:MM:SS format
# \@ : the current time in 12-hour am/pm format
# \A : the current time in 24-hour HH:MM format
# \u : the username of the current user
# \v : the version of bash (e.g., 2.00)
# \V : the release of bash, version + patch level (e.g., 2.00.0)
# \w : the current working directory, with $HOME abbreviated with a tilde
# \W : the base name of the current working directory, with $HOME abbreviated with a tilde
# \! : the history number of this command
# \# : the command number of this command
# \$ : if the effective UID is 0, a #, otherwise a $
# \\ : a backslash
# \[ : begin a sequence of non-printing characters, which could be used to
#      embed a terminal control sequence into the prompt
# \] : end a sequence of non-printing characters
# \nnn : the character corresponding to the octal number nnn


# Making a line of '-' character for separating prompts
# "tput cols" returns width of command line window.
_ps1_line() {
    echo -n $(
    for(( i=1; i<=$( tput cols ); i++))
    do
        echo -n "-"
    done
    )
}

# Colorizing Prompt
# $1 for background, $3 for foreground and $2 for making colour light or dark
_ps1_colour() {
    echo -n "\[\033[$1;$2;$3m\]"
}

# Clearing color to default
_ps1_colour_clear() {
    echo -n "\[\033[00m\]"
}

# Making text bold
_ps1_bold() {
    echo -n "\[$(tput bold)\]"
}

# Clearing tput format. here we use it for clearing bold.
_ps1_bold_clear() {
    echo -n "\[$(tput sgr0)\]"
}

# Making an array of what will be printed in each line. (each element of array for 1 line)
_update_ps1() {
    local parts=(
        "$(_ps1_colour 00 01 36)$(_ps1_line)"
        "$(_ps1_colour 00 01 34)USER$(_ps1_colour 00 01 33) ›››› $(_ps1_colour 00 01 34)\u"
        "$(_ps1_colour 00 01 34)HOST$(_ps1_colour 00 01 33) ›››› $(_ps1_colour 00 01 34)\h : $(_ps1_colour 00 01 33)\w"
        "$(_ps1_colour 00 01 36)››››$(_ps1_colour_clear)"
    )

    # After of generating array, it should be returned. it could be like this "echo -n "${parts[@]}"".
    # The problem is that it returns an space character between each element.
    # '\r' would be useful but it have side effect to prompt. it makes frozen characters.
    local length=${#parts[@]}
    length=$length-1

    echo -n $(
    for(( i=0; i<=$length; i++))
    do
        echo -n ${parts[$i]}

        # here we need to go to next line. but not for the last line.
        if (( $i < $length ))
        then
            echo -n "\n"
        fi
    done
    )
}

# initializing bash prompt variable
export PS1="${debian_chroot:+($debian_chroot)}$(_update_ps1) "

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#-----------------End of Custom bash prompt------------------
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