The Cookie Machine - Click here to drag window

DUMMY TEXT - Real text set in assets/js/theCookieMachine.js

If you can read me, I'm broken!

Views: 963     Votes:  2 
Tags: command-line   bash   environment-variables  
Link: 🔍 See Original Answer on Ask Ubuntu ⧉ 🔗

URL: https://askubuntu.com/q/1182025
Title: How to display all new variables after terminal started?
ID: /2019/10/19/How-to-display-all-new-variables-after-terminal-started_
Created: October 19, 2019    Edited:  March 3, 2021
Upload: June 16, 2024    Layout:  post
TOC: false    Navigation:  false    Copy to clipboard:  false


declare -p will show you ALL the variables defined outside of environmental variables which will include what you are looking for but also 121 other variables you are not looking for.

The secret is to capture the default variables when gnome-terminal opens and subtract that from the list of current variables to display only the new variables.

Using listvar

Instructions on creating the listvar function are below. To see how the listvar function works open a terminal and type:

$ listvar

$ hey="Hey World :/"

$ listvar
declare -- hey="Hey World :/"

$ Word=Something

$ Number=25

$ Ubuntu=16.04

$ listvar
declare -- Number="25"
declare -- Ubuntu="16.04"
declare -- Word="Something"
declare -- hey="Hey World :/"

Creating listvar

Add this to the end of your ~/.bashrc:

# Below must be at end of ~/.bashrc
# Display newly created variables
function listvar () {

    # Get current variable list
    mapfile -t CurrVars <<< "$(declare -p)"

    # Loop through each current variable
    for CurrVar in "${CurrVars[@]}" ; do

        # Skip over unwanted variables that are dynamic
        [[ "$CurrVar" == "declare -a BASH_"*    ]] && continue
        [[ "$CurrVar" == "declare -a FUNCNAME"* ]] && continue
        [[ "$CurrVar" == "declare -a PIPESTAT"* ]] && continue
        [[ "$CurrVar" == "declare -- _=\"\""*   ]] && continue
#        [[ "$CurrVar" == "declare -- sh="*      ]] && continue

        # Skip over variables used in our listvar function
        [[ "$CurrVar" == "declare -a SaveVar"*  ]] && continue
        [[ "$CurrVar" == "declare -- SaveVar"*  ]] && continue
        [[ "$CurrVar" == "declare -a CurrVar"*  ]] && continue
        [[ "$CurrVar" == "declare -- CurrVar"*  ]] && continue
        [[ "$CurrVar" == "declare -a OldVar"*   ]] && continue
        [[ "$CurrVar" == "declare -- OldVar"*   ]] && continue
        [[ "$CurrVar" == 'declare -- _="SaveV'* ]] && continue
        [[ "$CurrVar" == 'declare -- _="listv'* ]] && continue

        OldVar=false
        for SaveVar in "${SaveVars[@]}" ; do
            # Is current variable existing at time of save?
            [[ "$CurrVar" == "$SaveVar" ]]         && { OldVar=true ; break ; }
        done
        [[ $OldVar == false ]] && echo "$CurrVar"
    done

} # listvar


# Empty array to prevent doubling everytime ~/.bashrc is resourced
SaveVars=()
# Save variable list before user creates new ones in shell
mapfile -t SaveVars <<< "$(declare -p)"

Save your ~/.bashrc file and open a new terminal session to use listvar function.

⇧ Is it possible to turn off a specific USB port so it doesn't accept any device? Zenity progress: no window  ⇩