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WesternGun
Asked: 2021-05-25 02:40:53 +0800 CST

PS1 string full documentation and reference page

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After several frustrations I decided to share it so that next time I don't have to refer to my notebook but Google for it.

Is there some definitive documentation for PS1 strings accepted values?

  • escape letters
  • colors
  • Unicode chars
bash

1 Answers

    1. https://man7.org/linux/man-pages/man1/bash.1.html#PROMPTING. Just one thing: it means that each color should begin with \[ and end with \].
    \a : an ASCII bell character (07)
\d : the date in “Weekday Month Date” format (e.g., “Tue May 26”)
\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 hostname up to the first ‘.’
\H : the hostname
\j : the number of jobs currently managed by the shell
\l : the basename of the shell’s terminal device name
\n : newline
\r : carriage return
\s : the name of the shell, the basename 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 basename 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 $
\nnn : the character corresponding to the octal number nnn
\\ : 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
    1. colors
    txtblk='\e[0;30m' # Black - Regular
txtred='\e[0;31m' # Red
txtgrn='\e[0;32m' # Green
txtylw='\e[0;33m' # Yellow
txtblu='\e[0;34m' # Blue
txtpur='\e[0;35m' # Purple
txtcyn='\e[0;36m' # Cyan
txtwht='\e[0;37m' # White
 
bldblk='\e[1;30m' # Black - Bold
bldred='\e[1;31m' # Red
bldgrn='\e[1;32m' # Green
bldylw='\e[1;33m' # Yellow
bldblu='\e[1;34m' # Blue
bldpur='\e[1;35m' # Purple
bldcyn='\e[1;36m' # Cyan
bldwht='\e[1;37m' # White
 
unkblk='\e[4;30m' # Black - Underline
undred='\e[4;31m' # Red
undgrn='\e[4;32m' # Green
undylw='\e[4;33m' # Yellow
undblu='\e[4;34m' # Blue
undpur='\e[4;35m' # Purple
undcyn='\e[4;36m' # Cyan
undwht='\e[4;37m' # White
 
bakblk='\e[40m'   # Black - Background
bakred='\e[41m'   # Red
badgrn='\e[42m'   # Green
bakylw='\e[43m'   # Yellow
bakblu='\e[44m'   # Blue
bakpur='\e[45m'   # Purple
bakcyn='\e[46m'   # Cyan
bakwht='\e[47m'   # White
 
txtrst='\e[0m'    # Text Reset
    1. Unicode chars, my findings: With \x+hex_value, we can add Unicode chars into PS1 strings. How to find out Unicode of any char/string? Use echo <char> | hexdump -C. arg can be a string. The 0a at the end represents a new line. Because bash works on base of line buffer; must flush to know that this string is terminated. If you want to insert any character in a prompt string, delete every 0a except the last one, if needed.

    For example:

    echo 大 | hexdump -C
00000000  e5 a4 a7 0a                                       |....|
00000004

    So, you can insert the character in ps like:

    export PS1='\xe5\xa4\xa7'

    I found that with the converted string of Chinese characters, echo -e and printf both works expected, outputs the Chinese character, but in $PS1 it fails. So I was forced to assign a variable to the value of the command echo -e string or printf string.

    sentence=$(echo -e \xe5\xa4\xa7)
export PS1=$sentence

    This works well.

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