variables.sh

#!/usr/bin/env bash

IsShellVariable() { declare -p $1; } &>/dev/null
PrintShellVariable() {
  if IsShellVariable $@; then
    echo [\'$1\' as Shell Variable]: "${!1}"
  else
    echo [\'$1\' as Shell Variable]: "NOT FOUND"
    return 1
  fi
}

IsEnvVariable() { printenv $1; } &>/dev/null
PrintEnvVariable() {
  if IsEnvVariable $@; then
    echo [\'$1\' as Environment Variable]: "`printenv $1`"
  else
    echo [\'$1\' as Environment Variable]: NOT FOUND
  fi
}


PrintVar() {
  PrintShellVariable $1
  PrintEnvVariable $1
  echo
}

echo ASSIGNMENT
var1='hi i am var i'
PrintVar var1


echo DECLARE / TYPESET
typeset -r var2='hi i am var2'
PrintVar var2


echo PRINTF
printf -v var3 %s 'haiii i am var 3'
PrintVar var3


echo READ / READARRAY / MAPFILE
read var4 <<< 'hoi! ;) var 4'
PrintVar var4


echo EXPORT ASSIGNMENT
export var5='varrrr 5'
PrintVar var5


set +o posix
echo SPECIAL BUILTIN NOT POSIX MODE
var6='sixth var ^w^' :
PrintVar var6


echo REGULAR BUILTIN / COMMAND NOT POSIX MODE
var7='sevennth' read <<<''
PrintVar var7


set -o posix
echo SPECIAL BUILTIN POSIX MODE
var8='eighth var ^w^' :
PrintVar var8


echo REGULAR BUILTIN / COMMAND NOT POSIX MODE
var9='9th rawwrr' read <<<''
PrintVar var9
set +o posix


echo HOME IS ENVIRONMENT VARIABLE
PrintVar HOME


echo BASHPID IS SHELL VARIABLE
PrintVar BASHPID


echo EXPORTED HOME
export BASHPID
PrintVar BASHPID


echo DEFINE FUNCTION
function fn { :; }
PrintVar fn


echo EXPORT FUNCTION
declare -rx fn
PrintVar fn


echo DECLARE X
declare -rx var10='tenth variable'
PrintVar var10


echo ALIAS
alias var11='garrrhhh'
PrintVar var11


echo ARRAY
#declare -a var12=("foxtrot oscar xray")
var12=("foxtrot oscar xray")
PrintVar var12