Jtdcftul

I know that this question is quite old and answered, but I think I can add a bit of useful information.

In all the methods described above, the procedure that is suggested is:

• launch a terminal


• show the environment variables using env, or
  printenv or whatever

The problem of these solutions are that you are seeing the environment variables of the shell that is running into the terminal. You are not seeing the environment variables available to an application run, for example, directly by the graphic interface.

This is noticeable if, for example, you use your ~/.profile, or .bashrc, or .zshenv (depending on your shell) to modify the environment variables --- like the classic addition of directories to the path.

To see the environment variables available to the application started directly in the graphic environment, you can do the following (in Gnome Shell, I am sure there is an equivalent method in all the other DE):

• press Alt-F2


• run the command xterm -e bash --noprofile --norc
  

You now have a terminal with a shell that did not add any environment variables. You can use env here to list all your environment variables:

Obviously the new shell will have the environment variables added by the system files, but that variables should be available (by inheritance) to all programs in the system anyway.

I am posting this because it's the fourth time I have to search this trick again, checking my .pam_environment file. So now I will find it faster (and in the process, I hope helping someone else...)

You can see all variables with the declare builtin.

declare -p

If you're only interested in environment variables, use

declare -xp

Run help declare to see what the other options are.

To list the environment variables in terminal with CTRL+ALT+T you can use env command.

for example :

[raja@localhost ~]$ env

XDG_VTNR=1

SSH_AGENT_PID=3671

XDG_SESSION_ID=3

HOSTNAME=localhost.localdomain

IMSETTINGS_INTEGRATE_DESKTOP=yes

GPG_AGENT_INFO=/home/raja/.gnupg/S.gpg-agent:3691:1

GLADE_PIXMAP_PATH=:

TERM=xterm-256color

SHELL=/bin/bash

XDG_MENU_PREFIX=xfce-

DESKTOP_STARTUP_ID=

HISTSIZE=1000

XDG_SESSION_COOKIE=0250277dd805498381e96c05d88068b0-1364679772.845276-1676152201

WINDOWID=65011716

GNOME_KEYRING_CONTROL=/home/raja/.cache/keyring-N3QoQ2

IMSETTINGS_MODULE=none

QT_GRAPHICSSYSTEM_CHECKED=1

USER=raja

etc.

hope that helps.

In bash using compgen:

compgen -v | while read line; do echo $line=${!line};done  

env is a POSIX 7 way:

export asdf=qwer

env | grep asdf

Sample output:

asdf=qwer

It only shows exported variables: non-exported variables are not usually considered "environment variables".

Prefer that over printenv, which is not POSIX. Both seem to do the same thing without arguments: https://unix.stackexchange.com/questions/123473/what-is-the-difference-between-env-and-printenv

If you want a specific environment variable, rather than printing them all with printenv, you can for example print it by doing echo "$PWD"

Most solutions here either print only environment variables, or have the drawback that env or (set -o posix; posix) do not print values in parseable form (try to print variable A=$'arnb'...).

Here is a function that will print all variables, one variable per line, in the POSIX escaped form:

function dump_vars {

    local VARNAME

    compgen -v | while read -r VARNAME; do

        printf "$VARNAME=%qn" "${!VARNAME}"

    done

}

Thanks to @tmgoblin for pointing out the use of compgen -v.

printenv only lists exported variables,
CTRL+ALT+$
( "e$": complete-variable )
will list all variables.