The problem is that you're not quoting the
$ENV variable. As explained in
Enclosing characters in double quotes preserves the literal value
of all characters within the quotes, with the exception of $, `,
\, and, when history expansion is enabled, !. The characters $
and ` retain their special meaning within double quotes. The
backslash retains its special meaning only when followed by one of
the following characters: $, `, ", \, or .
So, enclosing a sequence like
\n in double quotes preserves its meaning. This is why, when not quoted,
\n is just a normal
$ printf \n
While, when quoted:
$ printf "\n"
An unquoted variable in bash invokes the split+glob operator. This means that the variable is split on whitespace (or whatever the special variable
$IFS has been set to) and each resulting word is used as a glob (it will expand to match any matching file names). Your problem is with the "split" part of this.
To illustrate, let's take a simpler multiline variable:
$ var=$(printf "foo\nbar\n")
Now, using the shell's
set -x debug feature, you can see exactly what's going on:
$ echo $var
+ echo foo bar
$ echo "$var"
+ echo 'foo
As you can see above,
echo $var (unquoted) subjects
$var to split+glob so it results in two separate strings,
bar. The newline was eaten by th split+glob. When the variable was quoted, it wasn't subjected to split+glob, the newline was kept and, because it is quoted, is also interpreted correctly ad printed out.
The next problem is that
printf is not like
echo. It doesn't just print anything you give it, it expects a format string. For example
printf "color:%s" "green" will print
color:green because the
%s will be replaced with
It also ignores any input that can't fit into the format string it was given. So, if you run
printf foo bar,
printf will treat
foo as its format string and
bar as the variable it is supposed to format with it. Since there is no
%s or equivalent to be replaced by
bar is ignored and
foo alone is printed:
$ printf $var
+ printf foo bar
That's what happened when you ran
printf $ENV_BEFORE. Because the variable wasn't quoted, the split glob effectively replaced newlines with spaces, and
printf only printed the first "word" it saw.
To do it correctly, use format strings, and always quote your variables:
printf '%s\n' "$ENV_BEFORE"