ENV shows partial environment only

Ruby
1

Hi!

It seems that Ruby is not picking up the complete environment
to be accessible through ENV–and I seem to recall this is by
design. Cursory poking-around in {hash,ruby,eval}.c did not
reveal anything particularly enlightening. Could someone shed
light on this if it indeed is done intentionally by Ruby and
not due to some strangeness in the C env functions?

An example session:

18:28:43 ruerue@yawn > ruby -v
ruby 1.8.5 (2006-08-25) [amd64-freebsd6]

18:28:51 ruerue@yawn > set | ruby -e ‘p ARGF.readlines.map {|l|
l.split("=").first if l =~ /^[A-Z]/}.compact’

[“BASH”, “BASH_ARGC”, “BASH_ARGV”, “BASH_LINENO”, “BASH_SOURCE”,
“BASH_VERSINFO”, “BASH_VERSION”, “BLOCKSIZE”, “COLUMNS”, “DIRSTACK”,
“DISPLAY”, “EDITOR”, “EUID”, “FTP_PASSIVE_MODE”, “GROUPS”, “HISTFILE”,
“HISTFILESIZE”, “HISTSIZE”, “HOME”, “HOSTNAME”, “HOSTTYPE”, “IFS”,
“LINES”, “LOGNAME”, “MACHTYPE”, “MAIL”, “MAILCHECK”, “OPTERR”, “OPTIND”,
“OSTYPE”, “PATH”, “PIPESTATUS”, “PPID”, “PR_BROWN”, “PR_CLEAR”,
“PR_LTGREY”, “PS1”, “PS2”, “PS4”, “PWD”, “RS_EMAIL”, “RS_NAME”, “SHELL”,
“SHELLOPTS”, “SHLVL”, “TERM”, “TERMCAP”, “UID”, “USER”, “WINDOWID”,
“XAUTHORITY”, “XTERM_SHELL”, “XTERM_VERSION”]

18:28:54 ruerue@yawn > ruby -e ‘p ENV.keys’

[“SHELL”, “TERM”, “WINDOWID”, “XTERM_SHELL”, “RS_NAME”, “USER”,
“TERMCAP”, “FTP_PASSIVE_MODE”, “PATH”, “MAIL”, “BLOCKSIZE”, “PWD”,
“EDITOR”, “XTERM_VERSION”, “HOME”, “SHLVL”, “LOGNAME”, “RS_EMAIL”,
“DISPLAY”, “XAUTHORITY”, “_”]

2

On Thu, Oct 05, 2006 at 07:57:43AM +0900, Eero S. wrote:

“LINES”, “LOGNAME”, “MACHTYPE”, “MAIL”, “MAILCHECK”, “OPTERR”, “OPTIND”,
“DISPLAY”, “XAUTHORITY”, “_”]
Are you sure all those variables are “exported”? (For instance, I
seriously doubt IFS is ever exported by a sane shell unless you
explicitly tell it to do so.)

3

Ruby’s ENV hash contains environment variables as returned by ‘env’,
not ‘set’, i.e.:

env

ruby -e ‘puts ENV.keys’

produce exact same lists.

Mike D.
http://www.rubywizards.com

4

[email protected] wrote:

“DISPLAY”, “EDITOR”, “EUID”, “FTP_PASSIVE_MODE”, “GROUPS”, “HISTFILE”,
“TERMCAP”, “FTP_PASSIVE_MODE”, “PATH”, “MAIL”, “BLOCKSIZE”, “PWD”,
harp:~ > sh

harp:~ > echo $FOO
ENV_BAR

You’re using Bash/ksh syntax, but just so you know, the greater-than
symbol (>) is usually reserved to mean csh or tcsh. $ is the canonical
non-root bash prompt. Switching them up makes examples like this one a
little confusing, and can be frustrating when you have to use someone
else’s machine for a second (e.g. to provide tech support through a VNC
session) and some commands fail for no apparent reason.

5

On Thu, 5 Oct 2006, Eero S. wrote:

“LINES”, “LOGNAME”, “MACHTYPE”, “MAIL”, “MAILCHECK”, “OPTERR”, “OPTIND”,
“DISPLAY”, “XAUTHORITY”, “_”]
it’s been a while, but are you confusing shell vars with env vars? i
think
‘set’ only reports the former:

harp:~ > export FOO=ENV_BAR

harp:~ > set FOO=SHELL_BAR

harp:~ > sh

harp:~ > echo $FOO
ENV_BAR

regards.

-a