UNIX, get environment variable

Question

I have a ridiculous question due to a ridiculous problem.

Normally if I want to get the contents of an environment variable in a UNIX shell, I can do

echo ${VAR}

Let's assume, due to my ridiculous situation, that this isn't possible.

How do I get the contents of an environment variable to stdout, without someone who is looking at the command itself (not the output), see the value of the environment variable?

I can picture the solution being something like echo env(NAME_OF_VAR) although I can't seem to find it. The solution has to work in sh.

PS I can't write a script for this, it must be a built-in Unix command (I know, ridiculous problem).

Racialism

Mike, are you ok? Are you being held with a gun to your head by the mafia in some warehouse? Is this a plea for help? – Arciniega

What's the problem ? A keyboard where '{' is invisible / inaccessible ? – Jalbert

@Tim .. my situation was almost that bad. But now, I'm OK – Racialism

short answer, emergency bug fix at work. the practices at this place are terrible (understatement of the year). the purpose was to ensure a user wasn't seeing a password that was supposed to be hidden. the previous developer had set up the design so that it passed a plain-text password through stdin to the application. i get sick just thinking of it. anyway, i was able to use skwllsps suggestion. a horrible fix to a horrible problem resulting in a horrible company making horrible software. – Racialism

Another situation where this is useful: on Windows, environment variables may contain parentheses, and you cannot do e.g. echo ${ProgramFiles(x86)} because the shell will try to attempt a subsitution. However printenv 'ProgramFiles(x86)' works. – Latton

Answer 1

You can do:

printenv VARIABLE_NAME

Exceptional

Ooh, something out of /usr/ucb. Impressive. – Muller

Answer 2

type the following command in terminal, it will display all the list of environment variables

printenv

now print the wanted variable like this:

echo $VARIABLENAME

Gumboil

Answer 3

Using ${!VAR_NAME} should be what you are looking for

> FOO=BAR123
> VAR_NAME=FOO
> echo ${VAR_NAME}
FOO
> echo ${!VAR_NAME}
BAR123

Coactive

Answer 4

How about this:

myVariable=$(env  | grep VARIABLE_NAME | grep -oe '[^=]*$');

Greg

actually you're probably better off using cut at the end e.g. ... | cut -d '=' -f2- – Greg

Answer 5

Do you mean something like this:

ENV() {
    printf 'echo $%s\n' $1 | sh
}

This works in plain old Bourne shell.

Bridget

I'd use more quoting myself: ENV() { printf 'printf "%%s\\n" "${%s}"\n' "$1" | sh; } – Moss

Answer 6

The solution really depends on what the restrictions are why you can't use a simple $VAR. Maybe you could call a shell that doesn't have the restrictions and let this sub-shell evaluate the variable:

bash -c 'echo $VAR'

Barbwire

Answer 7

( set -o posix ; set ) | grep $var

search for all unix-compatible format variables been used

Bobcat

Code only answers are discouraged on StackOverflow. Please try to elaborate a little as to why this is a correct answer – Belshazzar

Always remember to add explaination to the answer you post, so the users can understand the use of it. @Bobcat – Hettiehetty