laggardkernel

# A background process started within a loop may compete with
# the loop for stdin, which causes the `while read` loop stop
# after the 1st round.
 
cat << EOF >| tasklist.txt
1
2
3
EOF
 

laggardkernel

# catch empty strings into an array using `read`
# normal array assignment isn't able to catch emptry string.
 
unset k 2>/dev/null
while IFS=$'\n' read -r item; do k+=("$item"); done < <(printf "\n\n\n")
echo ${#k[@]}
[[ -z ${k[0]} ]] && echo "empty string is catched"


f() {

laggardkernel

  d_weechat:
    cmpignore:
    - '*/weechat_fifo'
    - '*/script/plugins.xml.gz'
    - '*/logs'
    dst: ~/.config/weechat
    src: .config/weechat
    trans: gpg-single "sec.conf"
    trans_write: gpg-single "sec.conf"

laggardkernel

Determine Whether a Command Exists in ZSH

The main purpose is to determine whether a command exists in PATH. Some of the following methods also support determine the existence of functions. The comparison focuses on speed, not support coverage.

❯ export TIMEFMT=$'%U user %S system %P cpu %*E total'

❯ time (for i ({1..100}) if (($+commands[tree])); then echo 1 &>/dev/null; fi)

laggardkernel

_env_init() {
  # init version manager without rehash on startup
  local SHELL_NAME="zsh"
  local init_args=(- --no-rehash zsh)
  local zshrc="$HOME/.zshrc"
  
  # For security on Linux
  [[ -n $XDG_RUNTIME_DIR ]] && local TMPDIR="$XDG_RUNTIME_DIR"

laggardkernel

function rsync-up {
  if ! (($#)); then
    echo "No host is provided" >/dev/stderr
    return 1
  fi
  local host="$1"
  local local_dir remote_dir cmd git_conf ignore_conf

  # https://git-scm.com/docs/gitignore

laggardkernel

Clear Scrollback Buffer

Crtl + L doesn't ensure scrollback buffer is cleared.

# https://unix.stackexchange.com/a/531178/246718

# Common function
function clear-scrollback {
  # https://invisible-island.net/ncurses/man/clear.1.html
  # https://unix.stackexchange.com/a/375784/246718

laggardkernel

By default, ZSH hook chpwd is not triggered on shell startup. The tutorial here provides some ideas to fix this.

Trigger all chpwd_functions on startup

We can use a trick to define a function run only once on precmd and destruct itself automatically.

function _self_destruct_hook {
  local f
  for f in ${chpwd_functions}; do
    "$f"

laggardkernel

Create a base class RedisPipeline, whichever Pipeline inherits it get a redis connection. Access to the redis conn with self.redis_server.

Dependency: scrapy_redis.

# defaults.py
REDIS_ENCODING = "utf-8"
REDIS_FAILED_URLS_KEY = "%(spidername)s:failed_urls"

laggardkernel

The post was created for the question [How to share config between vim and Neovim][question].

In this solution, we try to symlink ~/.config/nvim to ~/.vim, and make the conf compatible with vim.

# nvim conf dir: ~/.config/nvim
# vim conf dir: ~/.vim
# link the 1st as the 2nd with relative links