simple shell based prompt generated with promptline.vim

00-k8s-prompt.md

Sometimes a very simple prompt is useful - like creating documentation, or github issues. In those cases its still important to be able to tell the k8s context/ns

white [ctx/ns]

PS1='[$(kubectl config view --minify -o jsonpath="{.contexts[0].name}:{.contexts[0].context.namespace}")]$ '

orange [ns]

PS1='\033[01;33m[$(kubectl config view --minify -o jsonpath="{.contexts[0].context.namespace}")]\033[0m$ '

0README.md

fancy prompt in a single shell file (no pyhton/vim/nodejs whatever dependencies)

usage

2 ways to use it:

• permanently: store it in your home dir, and source it from bashrc (or similar)
• temporarly: if you want to try it once, or youa are in a container/vm just use eval

permanent install

curl -Lo $HOME/.prompt.sh \
  https://gist.githubusercontent.com/lalyos/0d28f171b365fcea51f5345e97b43279/raw/mypropmt.sh 

in your profile/bashprofile/zshprofile:

pw() { 
    if grep promptline -q <<< "$PROMPT_COMMAND"; then
        unset PROMPT_COMMAND
        PS1=${PS1_ORIG:-$}
    else
	PS1_ORIG="$PS1"
        . ~/.prompt.sh
    fi
}

Now you can switch between your original prompt and the fancy new one, by:

pw

one-off usage

eval "$(curl https://gist.githubusercontent.com/lalyos/0d28f171b365fcea51f5345e97b43279/raw/mypropmt.sh)"

k8s

I've added a k8s specific feature: if you want to see the CONTEX/NAMESPACE instead of git repo/branch

export K8S_PROMPT=1

switch back to git again:

unset K8S_PROMPT

switch back to usual prompt

If you used the permanent installation, just use the pw command to switch back (and forth)

pw

In case of the one-off installation (eval) you can switch back to a save version:

unset PROMPT_COMMAND;  export PS1="\w\$"

Bonus

you have now a new function switchNs which helps to quickly change the current namespace you are working on:

# switch to kube-system
switchNs kube-system

# switch back to last ns
switchNs

# or even with the "cd -" pattern
switchNs -

Origin

It is generated by promptline. The original project needs vim, and a plugin installed to be able to generate this shell file. So I've installed it and saved the generated script in this gist. With 1 change: i've switched off the fancy directory separator charaters which are not available in simple environments (cloud/containers)

mybashrc

kselect() {
  echo === actual KUBECONFIG=$KUBECONFIG
  select conf in $HOME/.kube/config* ; do
    echo === export KUBECONFIG=$conf
    export KUBECONFIG=$conf
    break
  done
}

kk() {
  echo export KUBECONFIG=$KUBECONFIG
}

eval "$(curl https://gist.githubusercontent.com/lalyos/0d28f171b365fcea51f5345e97b43279/raw/mypropmt.sh)"
export PATH=$PATH:~/.krew/bin

## kubernetes
alias k='kubectl'
alias kal='kubectl get all'
alias kg='kubectl get'
alias kgy='kubectl get -o yaml'
alias kgs='kubectl get -n kube-system'
alias kgc='k config get-contexts ' 

mypropmt.sh

#
# This shell prompt config file was created by promptline.vim
#
switchNs ()
{
    actualNs=$(kubectl config view --minify -o jsonpath='{.contexts[0].context.namespace}');
    local ns=${1:-$oldNs};
    : ${ns:? required};
    if [[ "$ns" == '-' ]]; then
        ns=${oldNs};
    fi;
    oldNs=${actualNs};
    echo "---> switching to: ${ns}";
    kubectl config set-context $(kubectl config current-context ) --namespace ${ns}
}

# switch between short and long prompt
function short() {
  if [[ -z ${shortprompt-x} ]]; then
    dir_sep=" / " dir_limit=3 truncation='...'; unset shortprompt
  else
    dir_sep="/" dir_limit=1 truncation='.' shortprompt=
  fi
}

function __promptline_host {
  local only_if_ssh="0"

  if [ $only_if_ssh -eq 0 -o -n "${SSH_CLIENT}" ]; then
    if [[ -n ${ZSH_VERSION-} ]]; then print %m; elif [[ -n ${FISH_VERSION-} ]]; then hostname -s; else printf "%s" \\h; fi
  fi
}

function __promptline_last_exit_code {

  [[ $last_exit_code -gt 0 ]] || return 1;

  printf "%s" "$last_exit_code"
}
function __promptline_ps1 {
  local slice_prefix slice_empty_prefix slice_joiner slice_suffix is_prompt_empty=1

  # section "a" header
  slice_prefix="${a_bg}${sep}${a_fg}${a_bg}${space}" slice_suffix="$space${a_sep_fg}" slice_joiner="${a_fg}${a_bg}${alt_sep}${space}" slice_empty_prefix="${a_fg}${a_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "a" slices
  #__promptline_wrapper "" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }
  __promptline_wrapper "${shortprompt-$(__promptline_host)}" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # section "b" header
  slice_prefix="${b_bg}${sep}${b_fg}${b_bg}${space}" slice_suffix="$space${b_sep_fg}" slice_joiner="${b_fg}${b_bg}${alt_sep}${space}" slice_empty_prefix="${b_fg}${b_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "b" slices
  #__promptline_wrapper "" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }
  __promptline_wrapper "${shortprompt-$USER}" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # section "c" header
  slice_prefix="${c_bg}${sep}${c_fg}${c_bg}${space}" slice_suffix="$space${c_sep_fg}" slice_joiner="${c_fg}${c_bg}${alt_sep}${space}" slice_empty_prefix="${c_fg}${c_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "c" slices
  __promptline_wrapper "$(__promptline_cwd)" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # section "y" header
  slice_prefix="${y_bg}${sep}${y_fg}${y_bg}${space}" slice_suffix="$space${y_sep_fg}" slice_joiner="${y_fg}${y_bg}${alt_sep}${space}" slice_empty_prefix="${y_fg}${y_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "y" slices
  __promptline_wrapper "$(__promptline_vcs_branch)" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # section "warn" header
  slice_prefix="${warn_bg}${sep}${warn_fg}${warn_bg}${space}" slice_suffix="$space${warn_sep_fg}" slice_joiner="${warn_fg}${warn_bg}${alt_sep}${space}" slice_empty_prefix="${warn_fg}${warn_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "warn" slices
  __promptline_wrapper "$(__promptline_last_exit_code)" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # close sections
  printf "%s" "${reset_bg}${sep}$reset$space"
}

function k8s-prompt() {
  if [[ "$K8S_PROMPT" ]]; then
    unset K8S_PROMPT
  else
    export K8S_PROMPT=1
  fi
}

function __promptline_vcs_branch {
  local branch
  local branch_symbol=""

  if [[ "$K8S_PROMPT" ]]; then
    ns=$(kubectl config view --minify -o jsonpath='{.contexts[0].name}/{.contexts[0].context.namespace}')
    #printf $'\u2638 '"$ns"
    printf "$ns"
    return
  fi

  # git
  if hash git 2>/dev/null; then
    if branch=$( { git symbolic-ref --quiet HEAD || git rev-parse --short HEAD; } 2>/dev/null ); then
      branch=${branch##*/}
      printf "%s" "${branch_symbol}${branch:-unknown}"
      return
    fi
  fi
  return 1
}
function __promptline_cwd {
  local dir_limit="${dir_limit:-3}"
  local truncation="${truncation:-...}"
  local first_char
  local part_count=0
  local formatted_cwd=""
  local dir_sep=${dir_sep:-" / "}
  local tilde="~"

  local cwd="${PWD/#$HOME/$tilde}"

  # get first char of the path, i.e. tilde or slash
  [[ -n ${ZSH_VERSION-} ]] && first_char=$cwd[1,1] || first_char=${cwd::1}

  # remove leading tilde
  cwd="${cwd#\~}"

  while [[ "$cwd" == */* && "$cwd" != "/" ]]; do
    # pop off last part of cwd
    local part="${cwd##*/}"
    cwd="${cwd%/*}"

    formatted_cwd="$dir_sep$part$formatted_cwd"
    part_count=$((part_count+1))

    [[ $part_count -eq $dir_limit ]] && first_char="$truncation" && break
  done

  printf "%s" "$first_char$formatted_cwd"
}
function __promptline_left_prompt {
  local slice_prefix slice_empty_prefix slice_joiner slice_suffix is_prompt_empty=1

  # section "a" header
  slice_prefix="${a_bg}${sep}${a_fg}${a_bg}${space}" slice_suffix="$space${a_sep_fg}" slice_joiner="${a_fg}${a_bg}${alt_sep}${space}" slice_empty_prefix="${a_fg}${a_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "a" slices
  __promptline_wrapper "$(__promptline_host)" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # section "b" header
  slice_prefix="${b_bg}${sep}${b_fg}${b_bg}${space}" slice_suffix="$space${b_sep_fg}" slice_joiner="${b_fg}${b_bg}${alt_sep}${space}" slice_empty_prefix="${b_fg}${b_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "b" slices
  __promptline_wrapper "$USER" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # section "c" header
  slice_prefix="${c_bg}${sep}${c_fg}${c_bg}${space}" slice_suffix="$space${c_sep_fg}" slice_joiner="${c_fg}${c_bg}${alt_sep}${space}" slice_empty_prefix="${c_fg}${c_bg}${space}"
  [ $is_prompt_empty -eq 1 ] && slice_prefix="$slice_empty_prefix"
  # section "c" slices
  __promptline_wrapper "$(__promptline_cwd)" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; is_prompt_empty=0; }

  # close sections
  printf "%s" "${reset_bg}${sep}$reset$space"
}
function __promptline_wrapper {
  # wrap the text in $1 with $2 and $3, only if $1 is not empty
  # $2 and $3 typically contain non-content-text, like color escape codes and separators

  [[ -n "$1" ]] || return 1
  printf "%s" "${2}${1}${3}"
}
function __promptline_right_prompt {
  local slice_prefix slice_empty_prefix slice_joiner slice_suffix

  # section "warn" header
  slice_prefix="${warn_sep_fg}${rsep}${warn_fg}${warn_bg}${space}" slice_suffix="$space${warn_sep_fg}" slice_joiner="${warn_fg}${warn_bg}${alt_rsep}${space}" slice_empty_prefix=""
  # section "warn" slices
  __promptline_wrapper "$(__promptline_last_exit_code)" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; }

  # section "y" header
  slice_prefix="${y_sep_fg}${rsep}${y_fg}${y_bg}${space}" slice_suffix="$space${y_sep_fg}" slice_joiner="${y_fg}${y_bg}${alt_rsep}${space}" slice_empty_prefix=""
  # section "y" slices
  __promptline_wrapper "$(__promptline_vcs_branch)" "$slice_prefix" "$slice_suffix" && { slice_prefix="$slice_joiner"; }

  # close sections
  printf "%s" "$reset"
}
function __promptline {
  local last_exit_code="${PROMPTLINE_LAST_EXIT_CODE:-$?}"

  local esc=$'[' end_esc=m
  if [[ -n ${ZSH_VERSION-} ]]; then
    local noprint='%{' end_noprint='%}'
  elif [[ -n ${FISH_VERSION-} ]]; then
    local noprint='' end_noprint=''
  else
    local noprint='\[' end_noprint='\]'
  fi
  local wrap="$noprint$esc" end_wrap="$end_esc$end_noprint"
  local space=" "
  local sep=""
  local rsep=""
  local alt_sep="|"
  local alt_rsep="|"
  local reset="${wrap}0${end_wrap}"
  local reset_bg="${wrap}49${end_wrap}"
  local a_fg="${wrap}38;5;220${end_wrap}"
  local a_bg="${wrap}48;5;166${end_wrap}"
  local a_sep_fg="${wrap}38;5;166${end_wrap}"
  local b_fg="${wrap}38;5;231${end_wrap}"
  local b_bg="${wrap}48;5;31${end_wrap}"
  local b_sep_fg="${wrap}38;5;31${end_wrap}"
  local c_fg="${wrap}38;5;250${end_wrap}"
  local c_bg="${wrap}48;5;240${end_wrap}"
  local c_sep_fg="${wrap}38;5;240${end_wrap}"
  local warn_fg="${wrap}38;5;231${end_wrap}"
  local warn_bg="${wrap}48;5;52${end_wrap}"
  local warn_sep_fg="${wrap}38;5;52${end_wrap}"
  local y_fg="${wrap}38;5;250${end_wrap}"
  local y_bg="${wrap}48;5;236${end_wrap}"
  local y_sep_fg="${wrap}38;5;236${end_wrap}"
  if [[ -n ${ZSH_VERSION-} ]]; then
    PROMPT="$(__promptline_left_prompt)"
    RPROMPT="$(__promptline_right_prompt)"
  elif [[ -n ${FISH_VERSION-} ]]; then
    if [[ -n "$1" ]]; then
      [[ "$1" = "left" ]] && __promptline_left_prompt || __promptline_right_prompt
    else
      __promptline_ps1
    fi
  else
    PS1="$(__promptline_ps1)"
  fi
}

if [[ -n ${ZSH_VERSION-} ]]; then
  if [[ ! ${precmd_functions[(r)__promptline]} == __promptline ]]; then
    precmd_functions+=(__promptline)
  fi
elif [[ -n ${FISH_VERSION-} ]]; then
  __promptline "$1"
else
  if [[ ! "$PROMPT_COMMAND" == *__promptline* ]]; then
    PROMPT_COMMAND='__promptline;'$'\n'"$PROMPT_COMMAND"
  fi
fi