Command menu (terminal,bash,fzf_reload)

#   Oct 21, 2022, 13:12:29  Command menu (terminal,bash,fzf_reload)


.bashrc :

#   folder,export PATH : Private path where the "type -p" command will find your own files.
#   source : Short .bashrc entry to make the original .bashrc more transparent. Custom settings and files in a separate directory. Easily portable, i.e. modular architecture.
#   $folder content :
#   $ ls $folder
#   backup.txt  bash_settings  cmd.txt  hdd.txt  install.txt  menupagedec  menupageinc  pacman.txt  swap.txt

folder=~/Downloads/bash && export PATH="$folder:$PATH" && source bash_settings



#   fzf reload subroutines bash script :

$folder/menupageinc :

#!/bin/bash
pages=($(< ~/pages));i=$(< ~/pagen);((i++));[ $i -gt $(< ~/pagem) ] && i=0 || :
echo $i > ~/pagen;cat $(type -p ${pages[i]})

$folder/menupagedec :

#!/bin/bash
pages=($(< ~/pages));i=$(< ~/pagen);((i--));[ $i -lt 0 ] && i=$(< ~/pagem) || :
echo $i > ~/pagen;cat $(type -p ${pages[i]})



~/Downloads/bash/bash_settings (or "$folder"/bash_settings) :

#   Command menu with multiple pages (bash, fzf).
#
#   fake readline (up and delete line) source :
#   https://stackoverflow.com/questions/18362837/how-to-display-and-refresh-multiple-lines-in-bash
#   https://stackoverflow.com/questions/22322879/how-to-print-current-bash-prompt
#
#   fzf insert = edit source :
#   https://github.com/junegunn/fzf/wiki/examples#opening-files
#
#   neccesary packages :
#   coreutils : head, tail
#   ncurses : tput
#
#   variables :
#   pn : page number
#   pmax : page maximum
#   pages,line,cmd,key
#
#   variables with files (for fzf reload) :
#   ~/pagen : page number
#   ~/pages : pages
#   ~/pagem : page maximum


echo 0 > ~/pagen                        # neccesary


function menu {

if [ $# -eq 0 ]                         # No page, then exit.
then
return
fi

pages=($@)                              # Loading pages (.txt) into a variable (array).
let pmax=${#pages[@]}-1                 # Number of text files (or pages).

if [ $(cat ~/pagen) -gt $pmax ]
then
echo $pmax > ~/pagen
fi

echo "$@" > ~/pages
echo $pmax > ~/pagem

tty=""
if [ "$TERM" = linux ]                  #   tty : --height=50% --border=vertical
then
tty="--height=50% --border=vertical"
fi

line=$(< $(type -p ${pages[$(< ~/pagen)]}) fzf --reverse --exact --no-color --no-info --expect=insert --cycle --bind "right:reload(menupageinc)" --bind "left:reload(menupagedec)" $tty)


if [ "$line" = "" ]                     # fzf escape, ctrl-c, empty string
then
tput cuu1 && tput el                    # fake readline (up and delete line)
return
fi

key=$(head -1 <<< "$line")              # https://github.com/junegunn/fzf/wiki/examples#opening-files (example of using --expect)
cmd=$(head -2 <<< "$line" | tail -1)    # https://github.com/junegunn/fzf/wiki/examples#opening-files (example of using --expect)

if [ "$key" = insert ]                  # only insertion
then
tput cuu1 && tput el                    # fake readline (up and delete line)
read -p "${PS1@P}" -eri "$cmd" cmd
fi

history -s $FUNCNAME $@
history -s $cmd

tput cuu1 && tput el                    # fake readline (up and delete line)
echo "${PS1@P}"$cmd

eval $cmd

}


#   Personal examples.

alias m='menu cmd.txt pacman.txt backup.txt hdd.txt swap.txt install.txt'

#   Older one page settings (out of habit).

alias b='menu backup.txt' s='menu cmd.txt' pk='menu pacman.txt' hdd='menu hdd.txt' swap='menu swap.txt' i='menu install.txt'