Unable to use environment variables in TCL (Linux/Unix)

Question

I'm having difficulties trying to use environment variables in TCL.

So I have a shell script which exports a bunch of environment variables so that my TCL scripts can use them later on.

set_vars.sh has the following code in it:

export TEST_ENV_VAR=Test

and the following works:

% puts $env(TEST_ENV_VAR)

Test

BUT once I place the environment variable in a operator or in quotes, nothing is returned.

% puts "$env(TEST_ENV_VAR) is in TEST_ENV_VAR"

is in TEST_ENV_VAR

Anyone know what the issue could be? Any help would be greatly appreciated.

Thanks for your time.

It seems the second time around, you did not run your set_vars.sh script. I tried your examples and they work just fine. — Hai Vu
– Hai Vu, Commented Mar 12, 2013 at 22:03

glenn jackman · Accepted Answer · 2013-03-12 22:16:30Z

4

There must be something you're not showing us:

$ export TEST_ENV_VAR=Test
$ tclsh
% puts $env(TEST_ENV_VAR)
Test
% puts "$env(TEST_ENV_VAR) is in TEST_ENV_VAR"
Test is in TEST_ENV_VAR

Note that env is a global variable, so if you're using it in a procedure, you must declare it as global

$ tclsh
% proc show_env1 {varname} {
    puts "does not work: $env($varname)"
}
% show_env1 TEST_ENV_VAR
can't read "env(TEST_ENV_VAR)": no such variable
% proc show_env2 {varname} {
    global env
    puts "works: $env($varname)"
}
% show_env2 TEST_ENV_VAR
works: Test
% proc show_env3 {varname} {
    puts "also works: $::env($varname)"
}
% show_env3 TEST_ENV_VAR
also works: Test

answered Mar 12, 2013 at 22:16

glenn jackman

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