plugin/percol: shellcheck & shfmt

According to `shellcheck`, the `_tac` alias simply doesn't work. At all. Ever. See SC2262 and SC2263.

clean_files.txt

@@ -92,6 +92,7 @@ plugins/available/hub.plugin.bash
 plugins/available/jump.plugin.bash
 plugins/available/node.plugin.bash
 plugins/available/nodenv.plugin.bash
+plugins/available/percol.plugin.bash
 plugins/available/plenv.plugin.bash
 plugins/available/pyenv.plugin.bash
 plugins/available/rbenv.plugin.bash

plugins/available/percol.plugin.bash

@@ -16,23 +16,18 @@ about-plugin 'Search&Select history with percol'
 _command_exists percol || return
 
 if [[ ${BASH_VERSINFO[0]} -lt 4 ]]; then
- _log_warning "You have to upgrade Bash to Bash v4.x to use the 'percol' plugin."
- _log_warning "Your current Bash version is $BASH_VERSION."
- return
+ _log_warning "You have to upgrade Bash to Bash v4.x to use the 'percol' plugin."
+ _log_warning "Your current Bash version is $BASH_VERSION."
+ return
 else
- bind -x '"\C-r": _replace_by_history'
+ bind -x '"\C-r": _replace_by_history'
 fi
 
 function _replace_by_history() {
  local HISTTIMEFORMAT= # Ensure we can parse history properly
- if _command_exists tac
- then
- alias _tac=tac
- else
- alias _tac="tail -r"
- fi
  #TODO: "${histlines[@]/*( )+([[:digit:]])*( )/}"
- local l="$(history | _tac | sed -e 's/^\ *[0-9]*\ *//' | percol --query "${READLINE_LINE:-}")"
- READLINE_LINE="${l}"
- READLINE_POINT=${#l}
+ local l
+ l="$(history | tail -r | sed -e 's/^\ *[0-9]*\ *//' | percol --query "${READLINE_LINE:-}")"
+ READLINE_LINE="${l}"
+ READLINE_POINT=${#l}
 }