Приведенный ниже код создаст подсказку, которая выглядит следующим образом:
В bash это нетривиально сделать из-за:
- Строка режима Readline принимает символы до того, как будет напечатано приглашение , что означает, что решения
printf не будут работать в некоторых случаях. Из-за этого:
- Удаление всех кодов ANSI CSI (например, цветов) для правильного расчета длины печатаемой правой стороны
- Нужно использовать
__git_ps1 для работы с git крайними случаями
__git_ps1 только выводит цвет при определенных обстоятельствах и только внутри $PS1- Разрешение цвета на выходе
__git_ps1 при удалении символов \[ и \] из его вывода (который не может быть вложенным)
- Завершение всего приглашения RHS в
\[ и \], чтобы гарантировать, что приглашение не делает странных вещей при просмотре / редактировании / завершении команд
#!/bin/bash
# _options=$(shopt -op); set -exu # Save and set shell options for testing
##################
# Set the prompt # Sourced from .bashrc
##################
# Select git info displayed, see /usr/lib/git-core/git-sh-prompt for more
export GIT_PS1_SHOWCOLORHINTS=1 # Make pretty colours inside $PS1
export GIT_PS1_SHOWDIRTYSTATE=1 # '*'=unstaged, '+'=staged
export GIT_PS1_SHOWSTASHSTATE=1 # '$'=stashed
export GIT_PS1_SHOWUNTRACKEDFILES=1 # '%'=untracked
export GIT_PS1_SHOWUPSTREAM="verbose" # 'u='=no difference, 'u+1'=ahead by 1 commit
export GIT_PS1_STATESEPARATOR='' # No space between branch and index status
export GIT_PS1_DESCRIBE_STYLE="describe" # Detached HEAD style:
# describe relative to older annotated tag (v1.6.3.1-13-gdd42c2f)
# contains relative to newer annotated tag (v1.6.3.2~35)
# branch relative to newer tag or branch (master~4)
# default exactly eatching tag
# Sets prompt like:
# ravi@boxy:~/prj/sample_app[exit]$ master*% u= | 30 Apr 22:27
_set_bash_prompt() {
# Set left hand side of the prompt
PS1="\u@\h:\w\$ "
#
# Git status
#
# Save current state of user shopt settings promptvars and extglob
local user_shopt
user_shopt=$(shopt -p promptvars extglob)
# __git_ps1 usually returns literal text "${__git_ps1_branch_name}" rather
# than the contained branch name, eg "master". This prevents calculating
# the length of the printable characers in the RHS string (used to move the
# cursor that many columns left from the terminal's right edge.) However if
# "shopt promptvars" is unset, __git_ps1 it will include the dereferenced
# branch name instead.
shopt -qu promptvars
# extglob is required for the ${variable//@(pattern)/} replacements
shopt -qs extglob
# Allow disabling git status and no error if __git_ps1 undefined
if [[ ! -v _disable_git_prompt && $(type -t __git_ps1 2>/dev/null) == function ]]; then
# __git_ps1 will only make pretty colours inside $PS1
local old_PS1=$PS1
__git_ps1 "" "" "%s" # force colour; no default round bracket (decorations)
# Strip "\[" and "\[": non-printable character markers. __git_ps1 outputs
# them however the whole of the RHS prompt needs to be included in these
# markers, and they can't be nested.
git=${PS1//@(\\@(\[|\]))/}
PS1=$old_PS1
fi
#
# Right hand side of prompt
#
local rhs="" # String to be printed on the right hand side of terminal
# Create a string like: "25 Apr 13:15"
local date_time
printf -v date_time "%(%e %b %H:%M)T" -1 # -1 is current time
# Format the RHS prompt
[[ -n $git ]] && rhs="$git | " #"
rhs+="\e[0;1;31m${date_time}"
# Strip ANSI CSI commands (eg colours) to enble counting the length of
# printable characters, giving offset of cursor from terminal RHS edge (from
# https://www.commandlinefu.com/commands/view/12043/remove-color-special-escape-ansi-codes-from-text-with-sed)
# Neither bash not sed support lookbehind zero-length assertions, so it's not
# possible to ignore "\\e", (ie a literal '\' followed by a literal 'e'), yet
# still remove "\e" (ie ESC)
local rhs_printable=${rhs//@(\\@(\[|]|[Ee]\[*([0-9;])[a-zA-Z]))/}
# or, in using sed (but requires exec):
# local rhs_printable=$(sed -e 's,\\[][]\|\\[Ee]\[\([0-9;]\)*[A-Za-z],,g' <<< "$rhs")
# Reference: https://en.wikipedia.org/wiki/ANSI_escape_code
local Save='\e[s' # Save cursor position
local Rest='\e[u' # Restore cursor to save point
# Save cursor position, jump to (right hand edge minus N columns) where N is
# the length of the printable RHS string. Print the RHS string, then return
# to the saved position and print the LHS prompt.
# Note: "\[" and "\]" are used so that bash can calculate the number of
# printed characters so that the prompt doesn't do strange things when
# command line editing/browsing/completion. Ensure that these are not nested.
PS1="\[\e[0m${Save}\e[$((COLUMNS - ${#rhs_printable}))G${rhs}${Rest}\]${PS1}"
eval "$user_shopt"
}
# eval "$_options"; unset _options # Restore previous shell options from line 2